"I think most people would agree that in most circumstances the existence of God is beyond objective measurement; I am a Christian, and I think that. That's the nature of faith. Would it be easier to debate more quantifiable concepts? Someone mentioned a discussion of if religion/atheism/etc is a net good or bad for society; that might be easier to debate clearly."
Well we can decide that here, I think. As a pure agnostic I have a lot to say on that topic that could help frame the debate.
For starters, there may in fact be people on either side who claim that they can know whether their belief is true, and it would I suppose be interesting to hear them attempt to prove that.
However as you rightly point out, most neutral and reasonable people would see such a debate as silly. But a far greater number of people seem to believe that they can objective establish that the chances of their belief being true are higher than equal with other options. So we could have that debate too.
But even if we all agree that those two debates are silly, there is more that can be said. Even if we agree that neither position can be proved or even suggested through objective measurement we can always set some parameters and go from there.
Let me explain what I mean. There are certain key "proofs" apologists of either side usually try to use to justify themselves. We could just focus on one of those areas within the context of the real physical world and have the debate.
Examples could be the validity of the theory of evolution, the veracity of the Bible, the truth or falsehood of an actual resurrection of Jesus, the true age of the universe, and so on. It can even be a bit more creative and even-handed than that if we like, with some ideas being:
1) This house believes that the implications of Big Bang theory imply a creator.
2) This house believes that the process of the birth of the universe all the way to the existence of humanity implies the aid of a supreme being
And so on.
That was the #2 I was talking about earlier but in terms of the "you should be ___" debate, there are many options there as well. You mentioned the net good or net bad on society question, which is interesting. There is also the net good/net bad on an individual person's well-being.
However I think, my opinion here, that the most interesting debate to most people of the category of people on Webdip is the question of how much of modern science is true, and what are the implications of the discoveries of modern science on the existence of God and trueness of the Christian religion?
There are many more, so if no one likes any of those we can keep formulating.