Expensive Cars. If you have to have one, buy a cheap one. One of the worst lifetime financial decisions you can make is spending money on cars, all of them get you to A to B. A used Prius is just about the most economical car you can buy for total cost per mile travelled. It would be nice if more cities had good public transportation systems, but unfortunately most don't. I love long island, getting around on public transportation is so convenient.
Edit: Something like this example prius is the way to go if you are trying to maximize your dollar. Drive it until the wheels fall off: