I normally don't advocate downloading and using free fonts... They are typically a little off, cheap-looking, or way, way, way over used. Smashing Magazine just posted a list of "25 New High Quality Free Fonts". A few of them are decent, and if you are a little broke in the design department, might be worth picking up and adding to your collection.
Be careful with free fonts, though... Especially if you're a designer. As with most things in life, you typically pay for what you get.