There are several fuels that are usable. In fact many of the cars manufactured today are designed as flex fuel vehicles or can easily modified. In Brazil the standard is that car manufactures MUST build flex fuel. The US Car manufactures say it cant be done but they are doing it in Brazil, They are using gasoline, ethanol, natural gas and diesel. Most cars are designed to run everything except diesel which requires a different engine. See http://www.washingtonpost.com/wp-dyn/content/article/2006/08/19/AR2... for more information. In having different fuel sources it creates competition between fuels and helps control the prices and creates some independence.
The bigger issue in adding more fuels is distribution. Unless you plan on making it yourself. The people who use fry oil have to filter the oil and mix a few minor chemicals into their mix. A little more work than driving up to the pump. Fortunately they also can use diesel as a backup supply. Getting back to distribution. You either need to build a bunch of fueling stations or get the fuel stations to add a few additional pumps to compete with their own fuel... If you can pull either one of those off I want to be your BEST friend.
Hydrogen requires a whole other process and still requires a distribution method or loads of power. You can chemically convert natural gas (a fossil fuel) to hydrogen or you can build simi portable systems that require loads of electricity to convert water to hydrogen. The conversion process is quite expensive Losses are quite large and fuel cell tech still needs work.
Ok there is one more tech that has really good promise. Electric cars. The distribution network is already in place mostly. You can charge at home or a friends house. Keep your eye open for a plugin and ask before using it. Maybe even offer them a few bucks for the power. The government is also putting chargers in various locations. There are charging stations being installed at shopping centers and places of employment and for now they are free to use. Depending on how much you spend you can have a range of 100 to 200 miles per charge. It is fairly easy to convert an gas car to electric if you are any kind of mechanic. Oh you want to race? There is a guy here in Portland that is running 10.5 in the quarter in a converted Datsun 1200 he hasn't raced in a while he says he can do 9.5 now with his new battery packs. There is actually a large group of people doing conversions across the world. I have done one myself and really enjoy driving past the fuel stations.
For racing they are cheaper to build and repair. You can pretty much calculate your time by the type of controller / motor / battery pack you use. If you blow a motor you can generally repair it for a few hundred. Rather than doing a total rebuild on a V8. Another advantage you get instant torque and power when you punch it. Also no need for a transmission and shifting delays. A V8 takes almost a full second to get to full power and you have to shift gears. I do enjoy shifting but I like the quiet shear power without all the work and delays.
I dont see electric cars being the solution to every ones traveling needs. I actually see a combination of several transportation methods in the future. City dwellers could use buses, Light rail, or electric cars and for long distance drives you could rent a car. Rural dwellers could use flex fuel of hybrid cars. There is no one fix for the issues.
The other big problem is to get the oil companies to get out of our governments back pocket. If you look at all the money flowing in the republican presidential races that doesn't look like that will be easy. Getting faithers to take responsibility that there really is a problem that god isn't going to fix. I mean they are supposed to be stewards of all things on this earth.