The other reviews of this book demonstrate what a touchy subject this is! Whatever your views I would recommend reading this book. It's fluent, well argued and engaging - although he is sometimes so angered by religious people that the fury starts to seep through and you can sense his knuckles whitening on the pen.
As with many theses the nuggets are sometimes tucked away. He casually reflects at one point how "believers" are actually atheistic about many gods (Apollo, Ra, Vishnu, Odin etc) - they dismiss almost as many gods as he does.
His scale of believing/not believing is interesting too: this isn't just a case of yes or no, there are many graduations on the way through - so, which are you? Quite atheistic but vaguely think there might be a God? Find out where you are on this handy, easy-to-read scale!
Seriously: this is a book that puts religious belief into perspective. If you are fifty like me, Christianity was probably a big part of your childhood education, and you challenged it at your peril. Like everything else your teachers believed in (corporal punishment, fair play, fitness, mind/body balance) in later life you have to assess the value of those ideas. Are you going to try to pass them on to your children? Are you sure that's right?
My tip - don't read the intro when you start: it's the angriest chapter, as it recounts the polemical (and sometimes downright horrid) attacks which have been made on Dawkins about the subject, so he's cross.
My own beliefs? Why should you care! This is an amazon review. It's about the book and whether it's worth reading. Enough with the ranting already.