I've often tried to debate this issue with my friends that tend to go a bit too far left in the environmental issues. There's this huge misconception that hydrogen is this free fuel. Guess they never did electrolysis experiments as a kid and waited around for hours for a tiny bubble in a test tube to form. (sure made a cool explosion when you lit the test tubes though).

I still say that the absolute immediate step is efficiency with our current power source. Hybrid vehicles work and seem to have no problems in implementation. In 5 to 10 years the technology should be mandatory in every vehicle in America to simply give us breathing room in exploring future power sources.

I'd like to see the technology taken one step further though. Current hybrid vehicles use piston engines for their primary power component. Why not gas turbine engines? If the main driving motors go strictly to electric motors, turbines can be used for the electrical generation. Direct drive of vehicles by turbine engines was always troublesome because they work best at constant speeds. The additional benefit to turbines is that they can use many different types of fuel such as gasoline, natural gas, alcohol, etc. Also, why in the world, if we're going to have hybrid vehicles, aren't they equipped with solar panels in their roofs? The panels certainly won't power the vehicle on their own but why not supplement with any energy sources we can find?

Can you imagine if we could also mandate every new house that's being constructed to have to have supplemental photo-voltaic cells or wind turbines attached to the power grid? It would add maybe 10 - 20,000 dollars to the cost of a new home but the owner would recoup much of that in 5 to 10 years. The huge economic impact on the solar industry would spur the technology and lower costs tremendously.