According to my better informed friends, there is enough oil in the ground to the point that we'll end up leaving some of it there (like with coal), having discovered a new energy source before oil actually runs out.
I think the problem with conservation on a grander scale is that those who have a vested interest in using fossil fuels have made an interest in conservation deeply unfashionable. The gentleman who opened this thread obviously felt he had to apologise/justify his comments by saying, above all else, that he "isn't a tree hugger". Well, I've never hugged a tree but it seems like a nice thing to do. I think it's pretty silly to dismiss someone as a fruitcake because they show an interest in such issues. There's nothing wrong in taking an interest in our collective future and being wise to future problems (especially the ones we're creating now). However running out of oil probably won't be one of them, unless Saudi goes like Iran like SLF said. Then things might get a little exciting, but that's not a question of ecology.