If your experience has been anything like mine, then having a logical discussion with someone very convinced of their opposing view is a very difficult thing.
It doesn't just happen with religion; it happens with everything. People refuse to see the other side of things and jump to anger very quickly. Opinions are hard to sway, sometimes a person's conviction seems stronger just because they're so loath to admit they could be wrong. Religion is very strong because it is very emotional. Atheism is simply logical. Put them together and you get a bloody lip and a cross in your face.
So for those of you who were once believers- Where was the switching point?
Were you ever on the opposite end of the rope as you are now?
Did you ever fight your battles in the name of the Almighty?
What- or who- changed your mind, and when?
Even if you spent most of your life agnostic, did something make you go off completely?