I'd second that. In fact, I think that knowing about evolution is probably a necessary prerequisite to being a rational atheist. Even Dawkins admits that it would have been pretty difficult not to believe in God before there was a plausible naturalist explanation for the complexity of life.

Of course, it's possible to know that there is a plausible naturalist explanation without really understanding the nuts and bolts of how it works (I'd probably put myself in that category), but maybe it really does help to hammer home the point if you really understand that The Creator wasn't necessary to make life, what exactly is He for?