The Argument from personal experience and why it fails to convince atheists.

This is a vastly varied field as personal experience is by definition personal and there are billions of theists in the world, and throughout history.

Basically it revolves around claims about miracles and feeling the presence of god. This is one of the poorest arguments anyone can present to an atheist, especially if the claims about a miracle are simply hearsay (e.g.: "my sister got healed when we laid on hands and prayed to Jesus").
Conversely if you could demonstrate a miracle to an atheist, empirically, then it might be the strongest argument you could present, but then it would not be an argument from personal experience anymore as it would have independant confirmation external to personal testimony.

So what is the problem with it? Well no one, including theists, would accept such unreliable testimony, if the tables were turned on them. No one would accept a tale by someone about something outragously improbable without some proof to back it up, unless you already accept the premises beforehand.

So for instance if you believed in ghosts, then you might believe someone telling tales of ghosts, but if you did not believe in ghosts, a tale about them would not convince you they exist.
If a hindu tells a christian that Vishnu revealed himself and healed their sister the christian would not believe them based purely on a unsubstantiated story, but if a fellow church member says Jesus did the same thing, then they might, unless it contradicted something doctrinal. Likewise if a Christian tells a Muslim that Jesus appeared and told them he was indeed the son of God, rather than a prophet of God, the muslim would consider the Christian either lying or deluded. This is because personal testimony is the weakest form of evidence you can provide, its highly subjective and easily contaminated by prejudice.

Now what if it is a 'confirmed' miracle of your faith, from history.  Does that make a difference?
Well not to someone not already a believer, because the miracles often 'confirmed' by religious authorities are highly dubious in their intent and purpose for validating the miracles. For instance the Catholic Church manufactured relics when it suited them, fabricated or accepted with little if any evidence miracle claims in the past when it suited them and nowadays, thanks to science, rarely if ever proposes any miracle might be authentic because they know it may be debunked if looked at closely by independant sources. The shroud of Turin is one glaring example of fraud and pussyfooting of the Church.

The holy books have claims of miracles in them, some witnessed by many people, even supposedly non-believers, does that make a better case?

The answer again is no. These are unverifiable 'proofs' written in the same book as the claims of miracles and the witnesses (of whatever type) are simply recorded as being witnesses, but there is no way to know what actually happened as there is no way to verify the statements. In many of the cases, no names are even mentioned, only numbers of anonymous 'witnesses'.
No theist would accept any of these as proof of a different religion being true over their own by itself.
If a theist will not accept such 'proofs' even when they already accept a truck load of supernatural beliefs, then why should an atheist that shares none of those beliefs?

Does that mean no miracle could impress an atheist? Well yes and no. No unsupported miracle will impress anyone not already a believer in that miracle or type of miracle. However if a 'miracle' could be shown to an atheist first hand, rather than a story or hearsay, then that is a different case entirely.
First hand experience is a lot more persuasive than 2nd or 10,000th hand.
However prayer studies have failed in this regard, or been shown to be badly or even dishonestly done, and no miracles have been recognised as valid outside of a religion's own followers unless they ascribe different purposes for the miracle (done by demons to trick you or something like that) by opposing faiths.

For me personally, if I saw limbs being regrown, as I watched, on amputees after someone prayed to only a particular god and no other, that would cause me to be impressed. It would need to be done openly and with proper sceptical double blind methods and repeated in different situations but if that kept occuring, only when one god was prayed to, then that might be enough for me to stop being an atheist. In the future this may NOT be enough as we may medically be able to regrown limbs but for it to spontaneously happen now after a prayer, well that would be, for me, a miracle.
However other 'cures' like healing bones, or curing cancer are often poorly documented and in many cases either misdiagosed in the first place, or had perfectly plausible natural reasons for what happened. I remember reading up on a famous case in Lourdes of a man who had a broken leg spontaneously heal on visiting the shrine, but after a bit of research found out that there was collusion with the doctor, outright lies and mislaid testimony and the leg had healed over 3 years prior to the trip to the shrine (he claimed the old scars was a 2nd miracle, which shows in hindsight the brass balls of the guy).
The claim originally sounds very impressive, the truth is a very different matter, often extremely deceptive and exaggerated.

Why the Argument from Design fails to impress atheists like me.

One of the most common arguments for any god is the argument from design, and is used by theists and deists alike, and even some atheists that believe in intelligent design (Raelians for example, although saying they are atheistic is stretching the term a bit in my opinion)

Many of these arguments use a variant of the Watchmaker argument or analogy, most famously proposed by William Paley over 200 years ago in his book Natural Theology.

In a simplified form, it goes along the lines of "If someone was walking on a beach and came across a watch (hence the name), you would immediately, on examination, determine it had a designer and did not appear by chance. All the gears would be too precise and purposeful to occur without a mind behind it. It is clearly evident that it was designed and therefore a designer exits." 

Some add that if an uneducated savage (rather than just anyone) that came across the watch they would work it it had to have a designer, even if they never saw a watch before. I think this only makes the argument worse, not better as it add extra elements that only clutter it up.

This is a form of telelogical argument that was aimed at showing empirical evidence for God rather than revelation or personal experience, which was more spiritual in origin.

One of the most popular current versions or subsets is the argument from irreducible complexity, brought forth by Dr. Michael Behe, although often misunderstood by theists (and some atheists) in regard to why Behe uses it. More on that later.

As an argument it is certainly more accessible to discuss than faith claims involving direct quotes from a holy book or miracle claims, but is it a sound argument?.
I would say no and there are many reasons why not. First a comment on the watchmaker analogy itself.

1. It is self defeating. The very act of spotting a watch, as an obviously designed object, on a beach of natural objects, like stones, sand, shells, seaweed, crabs, etc and recognising it as designed, in contrast to the natural world, BECAUSE it contrasts with the natural world, shows why using it to then surmise that the natural world is designed is an example of poorly applied logic. If the savage picked up a stone and on examination, HAD to come to the conclusion it was designed, then they might have had a point, but the only reason the watch stands out is because it is UNnatural. Personally this alone makes me laugh at this analogy as it self refutes its own argument.
2. The idea that a 'savage', (or in the timeperiod this argument was written, anyone not a white british gentleman) would have to come to the conclusion that a watch was designed is dubious in intent. IF we remove the 'savage' element for a second, the reason anyone would recognise a watch right off as designed would be because we KNOW they are, we already own them, see them being made, and understand vaguely how they work. Even if someone did not know what a watch was exactly, they would recognise metal working and craftmanship as humans have for thousands of years crafted stuff. Heck even before humans were humans there was some rudimentary crafting of stone knives and blades, so the act of design and purpose is fairly easy to recognise when facing something really alien to a natural environment (hard metal with lots of internal metal gears and clasps and dials and numbers). If they found a soft green rubber ball, no less designed than a watch, they might not realise it was designed as it might contain enough similarites with natural items to be assumed as a soft rock or animal. So basically this is nothing more than an carefully crafted (or designed) assertion of what they would like to happen, using, for the timeperiod in question (early 18th Century) one of the most sophisticated technologies available to really appeal to the populace and 'common sense'.

Moving on from the watchmaker argument, to the universe at large, theists often mention the constants, like the weak and strong nuclear forces, that if one (remember it has to be ONE) changes then all life we know (again the emphasis is on what life is currently like) would likely not exist.
This is an extremely dishonest slant on the argument, basically playing on probability numbers and the still poorly understood 'constants' of the universe.
There are many faults with this argument too, and the often misapplied false constants like the goldilocks zone the earth is in or the size of the sun, or the orbit of the moon.

1. Lets get the false constants out of the way first, they are often used in place of the actual constants, as theists often don't understand the 'real' ones but can grasp the easier idea of the earth being in a 'perfect' place for life or the moon being in the perfect orbit to help life exist and protect the planet from asteroids. None of these are constants, they change, have changed and will change. These are not the constants scientists discuss and to use them is to make one seem foolish. As far as each individual 'false' constant is concerned, while some do 'help' life exist, there are rebuttals to why they do not show design too. For instance the earth does get hit by meteors, as there have been multiple extinction events all throughout earth's history. Not exactly well designed if the moon and jupiter were 'designed' as a shield. Life hung on by the skin of its teeth (even before teeth evolved).
2. The constants that are actually accepted as constant are the way they are for reasons no one yet understands. Therefore using them as 'proof' of design is simply an argument from ignorance, as they are largely a mystery. A universe may settle into a state of set laws as it develops, and these 'constants' became constant after a while, they may be interdependant on each other, and therefore a change in one would affect others so that you cannot change JUST one and leave it at that. What would happen if many of these constants were slightly different, would they produce a different but still life supporting universe? It is possible. Yet apologetics don't want to hear that, they focus on changing ONE and how disasterous that would be to us, as if they knew what would happen in reality instead of just guessing.
3. The idea of the multiverse, that all possible outcomes do exist somewhere, and our constants happen to be the way they are here, and we are only aware of them because we exist in that kind of universe is one valid, if somewhat circular, response. It is often referred to as the antropic principle. Basically we only know the universe is the way it is, because we would not exist in a universe if it was different. This is a bit unsatisfying and I am not a huge supporter of the multiverse theories until I see more evidence than I have so far. I don't oppose the idea of multiverses at all, if they exist, fair enough, but the math is beyond me to be frank and I find some of the reasoning for them more wishful thinking than actual fact.

In general the idea that the universe is designed for humans is simply not true. It might be arguable that the planet earth was designed for bacteria to exist on it, as they thrive pretty much everywhere, but humans? 70% of the planet is water and most of that is undrinkable, most of the land masses have climates that are too harsh and the sun causes cancers, most plants are dangerous and most animals can hurt us or even eat us. If it was not for the eventual rise in technology we would be restricted to very small areas of the planet and constantly fear for our lives. This is shown by the near extinction of our species in Africa (well not human species really but our ancestorial species). The primary reason we survived is that we adapt and don't specialise. Exactly the opposite traits for a beloved creation that exists in a specially designed habitat for it's prosperity.
Its a bit like say the superbugs in hospitals were designed with love by the scientists that spend billions trying to kill them.

Now before I leave the topic I wish to discuss the idea of irreducible complexity. This is often discussed as if it shows deliberate design as if these organisms had to be created fully designed or they could not exist. This is not exactly what Behe was proposing IMO. He is not actually against evolutionary processes per se (common ancestry for instance), he does not believe in the organisms being poofed into existence in their current form by the word of God. Remember he is a bit more rational than your average frothing creationist. He is an I.D proponant and instead proposes that the organism that has some irreducibly complex feature, is proof of intelligent design, rather than chance. This means he has no problem with the idea that it developed, only that it could not develop by chance and there had to be a set goal in mind (thus a mind behind it). The necessary mutations were therefore made by a mind to set up these functions.
Now I could be wrong, but that is generally what I get when I hear Behe talk about his contribution.
He has an issue with Darwinian progression of undirected natural selection and feels that since these complex features need all their parts to fulfill their current function, they cannot occur in stages by chance.

However his arguments have been torn assunder quite sufficently to consider them largely nothing more than more aguments from ignorance. He offers no evidence for intelligent design except for knocking parts of natural selection. This is the old false dichotomy fallacy, where he sets up two options, misrepresents the one he does not like and knocks it, and declares the other option the winner. Its not only anti-science but outright lazy thinking.

The bacteria flagellum is his trademark example and rebuttals showing how it could have developed in stages has been made. He makes some major mistakes in his general thinking, these are cumulative issues, so it is important that you read ALL of them to understand the issue people have with Behe's line of reasoning.

1. That the current function was always the function or a required function of that organism in the ancestorial past. It has been shown that organs and other structures can change, and even absorb or co-op other functions through a species evolutionary history. Evolution is not a ladder of progress towards a set goal.
2. That all the elements needed for the current function have to be optimal, this is also shown as unnecessary. Organisms do not need to have perfect functions, only slightly better functions than their competition (if it aids in their propogation). This can result in refinement, or it can be a bridge to a merged or different function later on when another mutation / change of circumstances opens a pathway to a different line of evolutionary adaptation. The development of lungs for instance or the movement of cetain bones from the jaws of reptiles to mammalian inner ears shows that functions change or co-op already present features for new purposes.
3. That any part cannot be removed without the whole function failing. Using 1 and 2, this is no longer a valid argument as no one says that evolution has to follow that line of thinking. It's a strawman of evolution. An organism can develop and find benefits to parts of a future structure on their own, with their own, perhaps radically different, purposes before a mutation or series of mutations and circumstances compiled these together into what we see now. Behe somewhat accepts this while at the same time ignoring it and saying that because it's improbable (in his opinion) that they occur via indirect evolution they point towards a designer. However if it CAN happen, that there are indirect routes to irreducibly complex features, then how can pointing to it be evidence for design? All Behe really has is an argument from incredulity, in so far as he cannot believe it occured by natural selection and blind mutations alone so he proposes it must be caused by a designer.

Well that is all for now. This argument is a bit like a hydra as it has many heads that rise up where ever science lacks clear answers but when you get to the bottom of it, it is merely an assertion that if science does not explain something, and it looks amazing and baffleing, then a god or intelligent designer (a.k.a god) must be behind it.

Finally even if we grant a designer, it only gets you to a form of deism, an impersonal god that made the universe and that was it. For anyone to propose that is the reason they are a member of ANY religion is a serious failure of deductive reasoning.