Just came to say that I'm with So Boerd on free will being an illusion. 
[hider=clarification]Well, okay, that's not what he said, that's what he said atheists must or at the very least [i]should[/i] think.[/hider]

I'm atheist myself, and as far as I'm concerned, every "choice" we make is a consequence of something, rather than active free will. We may think we make a choice, but we were always gonna "pick" that choice, even though we might've been unaware of it ourselves.