Atheists, what are the most convincing theist arguments you heard of?

[Kernel Sohcahtoa]

I am sure you have heard some arguments for theism, maybe theists are convinced that they fulfill a burden of proof. 

Despite the problems these arguments may have, which one stands out the most to you?

I commonly hear atheists claim that the teleological argument, as terrible as it may be, is the most convincing of all theist arguments.

I personally think the Kalam Cosmological Argument is the #1.

The most convincing and reasonable thing that I've heard from a theist was actually not in the form of any particular argument.  It was actually through a thoughtful discussion that I had with a close friend (he is very intelligent and is definitely mensa material) of mine who is a practitioner of Christianity.

About a year ago, my friend and I started getting interested in watching some of William Lane Craig's debates.  Interestingly enough, in my friend's opinion, he thought that the case for theism couldn't be made solely by reason/logic: in his opinion, at some point or another, the theist must rely on his or her faith.  Hence, my friend was very open in pointing this out, especially when we were discussing WLC's debates afterwards.

Now, on another occasion, we eventually started talking about what would change the other's mind in regards to god.  I admitted to him that given my agnosticism, if we ever encountered some type of god-like life-form, then how would we ever know that this is actually the life-form who is worshiped by his particular religion?  Or put another way, for those Star Trek TNG fans (we both enjoy Star Trek), how can we differentiate Q from a god, since IMO, Q could easily play the role of whatever deity that people can think up?  Hence, long story short, he openly stated that it would come down to his faith; however, he was open to and cool with the possibility that what he believed to be a god could also be seen as just another form of life (or whatever) by someone else.

Edit

Hence, I appreciated my friend's open-mindedness and his acceptance that different people will have their own way of interpreting reality (this extends beyond the mere conversations referenced above) and that his way isn't the only way, nor is it necessarily the best way.