Audi has shown that TurboDiesel technology is ready for racing. They destroyed the gasoline powered Pescarolo's in Le Mans this year, even holding back they had a 2-3 sec advantage per lap. Now, I'm not saying the TurboDiesel is ideal for every race track (i.e. monaco might be a nightmare), but it's possible it could be developed to a very competitive point. After all, you can run a low fuel map and get 80 mpg, then a high fuel map and get 800 ft/lbs of torque. Current F1 v8's probably don't get much above 200ft/lbs.
Hybrids will certainly be the future, and we should develop it, but TDI power is already here. Although, I think it would be fun for every car to have a different type of engine technology.