Saw this slideshow on DaveRamsey.com. He's not my favorite financial "guru" but does occasionally have good stuff. The premise is that you can take the money youw ould have put into a new car, buy a used car, then invest the rest. Even if you step up the new car every year, you'll eventually have enough in the bank that you never need make a car payment again. Cool!

http://www.daveramsey.com/etc/lms/drive_free