In the future, we'll eat all our meals from toothpaste tubes, everyone will be beautiful and healthy, and we won't need cars, what with the proliferation of nuclear-powered jet packs. Prediction is such thorny business, though Toyota isn't making such a fantastical claim by suggesting that each of its vehicles will have a hybrid option available by 2020. Wired's blog seems to agree that by 2020, hybrids will have proliferated like rabbits, and we'll be awash in electron propulsion systems.

Efficiency is a large stumbling block if you're looking for a way to replace gasoline. It's pretty hard to better such an exceptional fuel, and several alternatives show promise but are nagged by inefficiencies or cost, and usually both.