most common arguments

what is the most common arguments that theists use to debate atheists? how do you counter?

Theist: "I have FAITH that God is real."
There is no way to counter this argument as it is not an argument. All religious arguments boil down to faith and once the theist drops that bomb the debate is over, it creates a stalemate. It is for this very reason that I don't debate religion anymore, unless I'm really bored.

Faith is a difficult one to overcome, and most times the mere mention of the F word is their way of letting you know that nothing you say will have any weight in the matter anymore.

I like to always bring up how people used to have faith that the earth was flat, or that we were the center of our solar system/universe, so there's always room for error in beliefs, or faith.

I also say that someone of a different religion holds just as strong of a faith about their own beliefs.
And in most cases that means 1 of them HAS to be wrong.

Or shoot holes in many of their religious teachings, which is usually easy enough to do, and ask if they're wrong about all this, what else could possibly be incorrect?

May not get you anywhere, but the points are out there.

THe ancient astronaught theory actually explians religeon and what it actually could be. If it were somehow proven, religion would no longer exist, or at least only exist in very ignorant and strong believers who would refuse to accept the truth.

Here's the biggest collection of humorous attempts to logically prove the existence of god(s) I have ever seen (definite parody).

Over 300 Proofs of God's Existence

The most common argument I hear is the argument that god is "supernatural", or something similar to that. I find this to be a last resort for theists when they have nothing better to say. This is not a real argument, as it treats god as being above all logic and reasoning, which makes no sense whatsoever.

By far, the most irritating is "look around you, how can you look (insert phenomena here) and still say there is no god"
My favourite response is "by thinking", but there are better responses. I often quote Carl Sagan, who said:
"How is it that hardly any major religion has looked at science and concluded, 'This is better than we thought! The Universe is much bigger than our prophets said, grander, more subtle, more elegant'? Instead they say, 'No, no, no! My god is a little god, and I want him to stay that way.' A religion, old or new, that stressed the magnificence of the Universe as revealed by modern science might be able to draw forth reserves of reverence and awe hardly tapped by the conventional faiths"-Carl Sagan
This is a truly irritating position, because it belittles the splendour of the Cosmos to say it was all made so that one infinitesimal speck could develop into us, a species so incompetent (in their eyes) that we need to be told it is wrong to murder someone.

The most common theist argument is certainly the cosmological argument. "The universe had to have been created!"

The problem with this argument is twofold;

1) If everything requires a creator, then the creator would, by the same logic, require a creator. Either the argument reduces itself to absurdity by accepting two mutually exclusive premises ("everything needs a creator"/"the creator doesn't need a creator") or it requires infinite regression (which would be impossible since there would be no (reason to assume a) first, uncaused cause).

2) If we assume that the universe had to have been created, we are merely assuming a creator. The assumption gives us no actual information about this creator or its qualities.