Some biofuels, ethanol, for example, are actually more harmful to the environment than Gasoline is. We'd be trading the lower costs of ethanol for a false sense of security while the environment further degrades. Also agree with biodiesel.

Personally, I think we should stop focusing on how to change our oil, but how to change our source of energy completely. Honda developed a car that runs on hydrogen!
Honda FCX Clarity - Hydrogen Fuel Cell Vehicle - Official Web Site

It's probably not usable yet because we still have trouble being able to split water efficiently into oxygen and hydrogen. But this will definitely cause the greatest climate change in our lifetime. That is, if it works...