Atheism is irrational.

[robvalue]

All these arguments are really saying are:

1. Some things need a cause. [Fair enough, although you should really talk about material and efficient causes to be clear]

2. Out of the things that need causes, there can't be infinite regression. [This is just an unsupported assertion, but let's allow it]

3. So there must be something that doesn't need a cause starting the chain.

How do we determine what that thing is? We haven't even narrowed it down to one thing. You can't just announce that there is only one thing is this set, and it happens to be what you want it to be. And we certainly haven't excluded reality itself as being one of the candidates. The criteria for not needing a cause is often "begins to exist", but (a) that's an unsupported assertion if applied uniformly to all of reality and (b) we haven't shown reality itself began to exist.