Iraqi gas runs good in my car.
But seriously, I think it will be a combination of fuels. for one thing the infrastructure for oil based fuels is already there and in place, secondly, there's just not much out there that gives you a better BTU return than gasoline, or diesel.
One of the problems with bio fuels is that under current technology, it cannot be introduced to a pipeline carrying an oil based fuel. (they're working on it), so for right now, the bio fuel can't use the existing oil infrastructure to be shipped cheaply, so it has to be trucked or barged, which is expensive., The other problem is what is happening right now in the midwest, these floods are going to impact food and biofuel production for the next couple of years, which means the biofuel market is as potentially shakey as the oil market.
The problem with electric cars is twofold, first, the battery replacement issue, which has already been brought up, and in reality, the carbon footprint of a current hybrid is about the same as an H1 Hummer. It looks good on paper, but unless you own a fleet of cars, you won't be feeling the added cost of hybrids.
lastly, for electric only cars, you'll just transfer the pollution from the tailpipe to the electric company, so there's no net gain. the fact is, oil based cars are really well engineered and thought out, actually, they are pretty efficient.
What I would think is going to happen is that we will see a change to gas/bio fuels such as the GM multi fuel cars now in use. I think we need to become more oil self sufficient by opening up more area to drill, and start openiing more areas to mine coal because it can be turned into oil using a coal to oil process.
All that being said, there's no reason why we can't change power sources for some things. the environmental wackos like to talk about cars being big polluters, but if you ran cars on bio fuels, which would clean up tailpie emissions, and start building some dams and reactors to generate power for complete cities, it would be a much "cleaner" environment (at least air pollution wise, there's always nuclear waste, but it can be managed relatively easily).
The biggest block to progress in my opinion is the freakin' enviro-wacks, you can't drill, you can't build dams, you can't build nukes and we should all be riding bicycles, and these clowns are not open to compromise in any fashion because they think we all should be vegans living in caves.