(My apologies, I'm doing a bit of inbox spring-cleaning, and I found this unanswered LJ comment, and I wanted to respond.)

I've encountered several atheists who are fairly self-righteous and pretentious about atheism and seem to want to "convert" everyone they meet. As a group, the only thing that ties us atheists together is the fact that we don't believe in god. In general, I think it's best to avoid lumping people together with a blanket judgement or perception.