Go Media's Arsenal: Free Textures, Brushes, Vector Art and More.
Go Media is a design studio which offers your funkier than average royalty free art at Go Media's Arsenal. Calling it Professional Design Weaponry, they have a multitude of interesting vector art, textures, brushes, animation and fonts at a fairly affordable price ($15 a pop for their cheaper sets). If you're not willing to pay for their stuff (who are we kidding we're a bunch of cheap bastards) they have a great freebies section. All they ask is to link to their site if you use 'em. They also have a tutorial section which seems worth looking at.