despite what people think, USA has cheep gas compared to the world... even tho its outrageous (expected to hit 7 USD's this summer). If you live in town and do not have kids, consider buying an electric assisted bike. ( http://www.thegostore.com/cosoxbelmo.html ) there; cheep to buy, street legal, can be driven on the side walk, do not require a license, and you don't have to pay any taxes on them.
if you have a family and kids and live in the city. consider buying a electric converted Geo metro.( http://e-volks.com/index.html ) They cost as much as the average used car. They cost less to operate ( less then .06 USD a mile) and are perfect for in city driving
if you travel more then 70 miles a day.....
you should buy a fuel efficient car.. like a Honda that gets 70 mpg