I think it's useful to consider non-hybrid options on two grounds: mileage and green house gas emissions plus our dependence on the Middle East. I own a 2002 VW TDI, 120k miles, run 100% biodisel in it and get 36mpg this being an auto transmission. would be 40 with a manual transmission. GHG emission reduction 75% from any other fuel/engine combination. The fuel is more expensive unless you make your own and I don't thus far. No Exon/Mobil, however. This solution is both cheaper than a hybrid in upfront cost and, I'd suggest, is environmentally superior.
Even without bio-diesel, diesel cars with good emissions controls and low sulfur fuel are "environmentally friendlier" than the current hybrids. The processing of diesel has less of an impact that gasoline and the mileage of a diesel car normally equals a Prius.