I recently replaced my old bucket of bolts with a new hybrid. It drives really nicely and has mileage greater than 50 mpg. I'm very happy with it, it drives great.
I think I did a good job maintaining the old car for a while. Cars have an environmental cost not just to drive them as the media tells people, but also to build them.
I do think it's a problem that the most basic cars have been removed from the market. The Hyundai accent, for example, cost 20k and had an MPG of around 36 mpg am that was pure gasoline. They discontinued it to sell more exspensive cars.