Hi subbie
Dammit, I took the trouble to read all the way through this discussion and thought what a lot of nonsense was being said, and then you and Caffeine ruin my chance of glory by talking some sense.
You are absolutely right to point out that "evidence" is not (necessarily) the same as "proof" and for most of this discussion that has been a point of confusion.
However, I would say that absence of evidence CAN be proof of absence depending on the parameters.
For example, to get back to the original topic and the question of the existence of God, it entirely depends on what the definition of God is. Of course, to my knowledge all religions quite deliberately keep the definition of their God vague so as to ensure that its existence can never be disproven - how can it be if we don't know what we're talking about? But if you were to claim, say, that God is an old man who lives in a particular cave, and you fully explore that cave and find no evidence of any old man, then I would consider that proof of that God's non-existence, as much as anything can be proved.