The problem with that argument is that it presupposes that if there is a God, he must be the God of the Christian Bible. I'd say that even if we could prove with 100% certainty that there is a creator, we're still no closer to figuring out who or what that God might be. The possibilities are almost endless. It could be a highly advanced alien civilization that engineered this whole thing. Maybe there is one creator god but nothing like the Christian god at all.
Point being, alot of people say they don't believe God because the version of God that they are familiar with doesn't sound believable to them. I'll admit when I think of God I default to the standard western Christian God in my mind, but really there is no reason to assume that's more likely to be correct than any other, far as I can see.
