I'd like to take some time to contemplate my navel at this question.
The context was a seminary student, evidently unaware of Occam's razor, asking why I would disbelieve in a god that, by definition, had no physical evidence of its existence whatsoever. His justification for choosing agnosticism under such circumstances, rather than atheism, was "Well, you don't know that he doesn't exist."
I wonder if I should have brought in Dawkins's, "Well, we're both atheists. It's just that I disbelieve in one more god than you do."