A writer for the Economist found that after moving from England to Texas a few years ago, hybrids were in short supply so he checked out used cars instead. A 2001 Honda Civic turned up with 35,000 miles and a $10,800 price tag. It was immediately getting 30/34mpg city/highway and after some basic maintenance like new filters the highway mileage jumped to 40mpg even at 78mph on Texas highways. Just having a lighter, smaller engined car combined with regular maintenance can give you pretty much the same real world mileage as a hybrid.
[Source: The Economist via Autoblog]