Atheism's Definition - Stanford Encyclopedia of Philosophy

[Darkstar]

And if I call myself a agonistic (like I do) then what?

I think we're conflating knowledge with belief again. I agree with much of what FallentoReason said, but I don't think that shifts the burden of proof wholly to atheists. Until theists come up with a falsifiable claim, it would be absurd to expect opponents to disprove it absolutely. Rather, in the lack of any evidence for a god, I would say that this gives us no reason to believe a god exists and "proves" (i.e. beyond a reasonable doubt) that god doesn't exist.

More to the point, belief god does not exist is not incompatible with an agnostic stance. I personally believe god doesn't exist, but I am also agnostic about that belief.