That's one of the problems, I think. I imagine there's some sort of event/happening that might steer me towards a (re)belief in God, but short of dying and then meeting him at that point, I'm not sure what that would be.
I think one of the big issues I have with belief, is my understanding that the vast majority of the instances that people reference as a sign that God is real, and what they might use to bolster their faith, they were actually told ahead of time what to look for. So, perhaps you get goosebumps while visiting the grave of a lost loved one, and you had previously been told that that is a sign from above. Especially in such a situation, where you're yearning for a glimmer of hope that you may one day reunite with this loved one who has passed on, you're going to WANT to believe that those goosebumps are what you've been told they are. You've already been predisposed to interpret that physical sensation with something from beyond. So all that needs to happen is for such an occurrence to happen at the right time, and BOOM you've made the connection and giving that sensation more weight than just a physiological reaction to the emotions you were under at the time, and that light gust of wind that would have blown there if you were present or not.
I believe in the power of placebo, and I believe it plays a part in the vast majority of instances where people think they are "touched" by the presence of God, or otherwise experience his presence. They have already been told what to look for, and they have already been given an explanation of what those sensations are, and where they come from. Factor in that, assuming they're already a believer, they WANT to experience these things, and it's quite within the realm of human ability to actually manifest these feelings themselves (goose bumps, sudden feelings of warmth, etc.).
So, that's an issue I have with "proof" is that it is highly dependent on someone wanting proof, and being very open to the idea of that proof coming. Their radars are on ultra-sensitive mode, constantly scanning for anything resembling these feelings/sensations others have no doubt gleefully described to them.