Is atheism a belief?

[Duty]

 If someone says, "Do you believe in god?" a natural enough question is "Which God do you mean?"  I don't think you'd ask a Biblical Christian that.

Yeah that's what I say when asked. It often leads to an opportunity to reel off the names of Vishnu, Thor, Zeus etc when they say "you know, God" and you reply "Yeah but which one? Ganesh? Odin? Vulcan?" etc. With any luck they wind up looking and feeling confused, vulnerable and stupid - job's a goodun!