Religious belief is something that is so deeply personal, and so fundamentally based on faith, that it still dumbfounds me that anyone would argue over it, let alone kill each other. In my opinion, if you are fully confident in your convictions, what someone else has to say about them can't possibly touch you. A lot of my atheist friends have told me that they're "afraid" to tell people that they're atheists because their beliefs will be attacked. I think to myself, so what? Defend if you feel you must, but what's the point? Their opinion should have no influence on you.
As a very committed agnostic, I have been attacked by both sides. The standard attacks come from religious believers. I just shrug my shoulders. They're entitled to their opinion. The atheists have often told me that I'm an agnostic because I'm not "brave enough" to be an atheist. This amuses me. How can it possibly be cowardly to admit that you don't know the answers? The great irony is that believers and non-believers are more alike than they think; both take great comfort in the fact that they know the truth, even though the truth is unknowable at this time.
It makes me sad that it's nearly impossible to talk about religion with a large, diverse group of individuals without insults being hurled. I love religion and I love to talk about it. I'm fascinated by peoples' beliefs, and I'm not easily shocked or offended by them. Religion was my field of study in both undergraduate and graduate school. I've pretty much heard it all already, and have learned to keep an open mind (within reason, of course. I don't condone underaged girls getting married to men 3 times their age, or human sacrifice, for example).
But most discussions are ruined by people who just can't be content with letting others believe what they want to believe. I wonder if tearing others down is an inherent part of being a human being, or if it is learned behavior. Whatever it is, I wish we'd all grow up a little bit and just learn to share the world without being so judgmental and self-righteous.