I see all this hypothesising about how the world will be once the oil is gone if we don't find a replacement fuel source (which we probably won't). The answer is quite obvious and we've been there before - we will live like we did before we used oil. We managed fine without it for a very long time and we'll manage fine without it again, I just don't see what the big deal is. So the oil runs out, oh well, the party's over, back to the horse drawn plow for us. Big deal.

OK, it won't be an easy transition, in fact a lot of folks will die a miserable death, but hey, that's nature's way, it's called natural selection. The ones fit to carry on the species will, and a few generations later once the planet starts healing we'll be better off allround as a species. Basically, it's all good news.