Proposing that the world would have peace without religion is comical. Human nature will absolutely not allow us as a species to get along consistently without some kind of conflict. Religion, in my opinion, is certainly a big platform for human conflict - as proven in our history and current events. However, take a look at this thread: we have atheists arguing against atheists about levels of belief and how people define their beliefs. Perhaps I'm jumping to conclusions, but it seems to me that it's just in human nature to argue, be territorial, be jealous...even obnoxious. I can admit that I'm human, and I'm ALL of those and then some. I can be a bitch sometimes for no reason and I can admit that. If world peace were up to me, even as an atheist, we'd be fracked!
Anyways...here's a funny read: Hate Mail to Richard Dawkins
http://old.richarddawkins.net/letters/ugly