I see your point, however, some people in history have been forced into the 1 or 0. Christians have been killed by atheists/other religions for refusing to denounce their christianity. Atheists have been killed by Christians for refusing to admit the existence of God. Both have been forced to choose, on pain of death. Denouncing Christianity or atheism (especially atheism) would be a pretty easy thing to do unless you're absolutely certain. I'd say that's a pretty good case for arguing 1 or 0 (or maybe just plain human stubborness, I don't know).

As far as the probability of God goes, I think there is a 0.0000000000001 chance that Santa, as described in popular myth, actually exists. That doesn't really make me a Santa agnostic.

For me, the probability that God of the bible exists is 0. Absolute 0. The probability of a personal God who interacts with world or people in any way, is absolute 0. The probability that Jesus was some messenger of God is absolute 0. The probability that a higher, universal power of some kind exists is about 10% for me.