I hear that the best fuel-efficient/hybrids will be released in late 09 and early 10. And further there is a good chance that Obama will offer incentives to buy a fuel efficient car. Waiting 6-9 months may be worthwhile.
If you can't wait, then I suggest a Prius (have not driven it myself - but its hard to get away from the positive buzz about this car).
If you'd like to give Detroit a hand - check out the ConsumerReports list of best American cars of 2008 - http://blogs.consumerreports.org/cars/2008/03/american-top-p...