Can an Atheist argue someone out of faith?

[Ace Otana]

I was hoping that you could tell me why you don't personally believe in God.

No evidence. Theists claim there is a god (so the burden of proof is on them) and they fail to provide evidence for their claims and so I reject them. Ta-da! That's why I'm an atheist.
Well also because none of what they claim make any sense.

what you think are the best arguments against Christianity, or the concept of God in general.

Well not argument exactly. Knowledge. God exists only in the unknown. The more we know the less places people can put god. God used to be the sun, the moon, the earth, the stars, ect, ect. But as we gain knowledge, god can no longer be the sun, moon, earth or stars. Because we know what they are. If we can go further and know what and how the universe came about, god can no longer be placed as an explanation. So knowledge is the best thing we have against religion.

I want to see how persuasive you can be.

I don't persuade people from believing in the extremely improbable. They can believe in whatever idiot fantasy they wish.

and especially your own story of how you came to Atheism.

I was born atheist and I have remained an atheist. Due to lack of evidence for a god or gods. The more I learnt, the more I doubted. I've only ended up becoming a stronger atheist, not a weaker one.

Why does the theist have the burden of proof?

Because theists are the ones who claimed there is a god. There-for, it's down to you theists to prove it. We atheists aren't expected to do anything. We can just sit back and wait for you to provide the evidence for your claims.