I'd like to see some information on the energy in/energy out thing. It's definitely a limiting factor if we were to hit it, but of all the analysis on peak oil I've seen, it's never about that. It's always about it just being more and more expensive to extract remaining reserves. What I'm mainly referring to is how this dynamic plays in economics as a fluctuating plateau for a long time. If oil hits a certain cost level (currently that level is around 100$ a barrel), it is predicted to create a recession, as that always has in the past. Then the recession makes oil cheaper due to drop in demand, then demand rises, then oil price rises, rinse repeat. Alternative sources are either going to have to get pretty cheap and defeat those looking to destroy them, or oil is gonna have to get expensive enough that there's no choice but to engage in alternative fuels. We're technologically not too far off on alternatives either, but the biggest hurdle is to stop letting oil billionaires and shareholders soak us for all we're worth

I'm pretty sure that when scientists and the like discuss peak oil, they're referring to the oil they already deem as extractable with a net energy gain. We do know there's a crapload of oil in the ground that can never be touched. In fact, I think that even the easiest to evacuate fields are still left with about 1/3rd left just because it can't be extracted with a net energy gain. I'm not positive on that though