Andy- I respect that you called yourself out on that prediction. When prices began to rise, I was tempted to bring up the thread where you made the prediction. I've much respect for people that admit when they were wrong. Also much respect for making a prediction in the first place.
Your forecast for oil prices seems reasonable to me. The only thing I would add is that oil will always be necessary since our world is made of it, and certain transportation such as planes, trains, and ships will need oil for the foreseeable future. As easily obtainable oil is exhausted, prices will increase as the difficulty in mining it increases.
All that said, I believe the price of most everything will drastically reduce in the next 50 years as automation and robotics drives the cost of production ever closer to near zero marginal cost. Finding useful employment will become more challenging as most jobs are eliminated.