An excellent quotation_
I am an atheist, out and out. It took me a long time to say it. I've been an atheist for years and years, but somehow I felt it was intellectually unrespectable to say one was an atheist, because it assumed knowledge that one didn't have. Somehow it was better to say one was a humanist or an agnostic. I finally decided that I'm a creature of emotion as well as of reason. Emotionally I am an atheist. I don't have the evidence to prove that God doesn't exist, but I so strongly suspect he doesn't that I don't want to waste my time.
Personally, I've always used a metaphor to explain why I'm an atheist and not an agnostic_ If you were a vegetarian, but said that maybe someday you might consider eating meat again, would that make you less of a vegetarian? Would you be veg-nostic? No.
Right now, all the evidence leads me to believe that there is no higher power intervening in our lives. However, I hope that I never become so nearsighted, in any of my beliefs, that that I ignore obvious proof to the contrary.