Theists: What is the most compelling argument you have heard for Atheism?

[Brian37]

If science can't test and falsify it why the fuck should it be assumed? Because you like it? [1] Again, so what, Muslims cant test and falsify Allah. Jews cant test and falsify Yahweh. [2]

I have a giant invisible pink unicorn whom magically makes me truck loads of ice cream that suddenly appear in front of me upon praying to it. Now, that would be a claim beyond nature. But since you cant test and falsify that claim we have to assume it is true by default? Bullshit.[3]

I don't play "if ifs and buts were candy and nuts".... And especially way after the fact. That was then and this is now. If you insist on being stuck in bronze age superstition, again, that is your baggage, but don't expect me to take it seriously.[4]

1. Because I am convinced of the evidence for my belief. 
2. We can examine all religious belief systems for evidence, internal consistency, and how well it explains reality, and compare them to each other. 
3. Sophisticated rebuttal. How many people have seen the unicorn? Did they spend 3 years with it? Did it teach them things that made sense on a level not considered before? Did it perform miracles, die on a cross, and then rise again? Did it then spend another 40 days making appearances and talking to people? Did the people that it spoke to, in turn go out and put into practice what the unicorn instructed all over the known world--often at great personal costs? Do the people that follow these instructions testify of internal changes that were promised? Has this been going on for millennium? Are there over 2 billion people that believe that all these things happened in this order? If not, you are comparing apples to oranges. 
4. You have such a simplistic picture in your head about what you are arguing about and therefore you think your objections carry some intellectual weight. The picture is wrong and your objections are simplistic and mundane. You seem to be just another angry New Atheist that thinks their ideology is something special--it's not--just recycled, philosophically bankrupt opinion with some anger thrown in.

We don't have to go beyond your first numbered bullet.

"1.Because I am convinced of the evidence for my belief"

Yea ok. I am sure you believe it and? 

And others are "convinced" of the "evidence" of the Koran"

And others are "convinced" of the "evidence of the Torah/Talmud"

And others are "convinced" of the "evidence" of Buddha.

And others are "convinced" of the "evidence" of the Hindu Vedas,

How about considering someone introduced you to those claims when you didn't have the best data? How about considering when you first bought the claim you were merely seeing others whom you thought were smart and right and wanted something to belong to?

I am sure you are convinced, but so what? Again, others are "convinced" they are correct and you are wrong.

Maybe it merely amounts to the religious of the world of all labels buying a claim without kicking the tires and not having the knowledge to question what they are sold?

Take any argument you might make, and wherever you use "my god" or "my book" replace it with another you don't buy into yourself. Then ask yourself if the argument you use yourself would still work.