Hydrogen, perhaps?
The Hindenburg disaster taught the world a thing or two about the dangers of hydrogen. Despite of this, research into use of hydrogen as an energy source is more active than ever. The reasons are rather simple: hydrogen is highly energy efficient, and when you burn hydrogen you get water wapor, which is nice, to say the least.
I ran across this Slashdot article about a hydrogen-based scooter, which in turn led me to a very interesting PDF titled Hydrogen Storage via Sodium Borohydride by Ying Wu from Millennium Cell Inc. These guys have figured out how to use sodium borohydride as an intermittent medium for hydrogen storage, and the bi-products produced from the hydrogen-extraction reactions can even be recycled back into sodium borohydride.
I'm no chemistry whiz but I'd be willing to bet that our planet would be way better off using something like this compared to using fossile fuels. If it would be possible to use solar energy in the recycling process we'd have a truly sustainable energy solution... It's truly a shame so little research is going into stuff like this. I'd bet that channeling the world's cumulative military expenses over a single year into research like this could realistically fund making technology like this a large scale reality. Why can't people just get along?