Diesel: fuel of the future?   stance: highly plausible:
Recently, engineers have recreated the diesel engine. No longer is it the loud smoke chugging brute of an engine. Rather, it now has mileage that rivals hybrids (a new VW diesel car gets 75 miles to the gallon, beating out the Toyota Prius) and has more eco-friendly emissions than ever before.
Its not smart to bank our future on fossil fuels and the like forever, however until we get more efficient electric/other technologies it seems like a great stepping point.
(also, hydrogen as a combustive fuel is being researched right now and seems quite plausible as well)