I've redrawn countless raster logos in Illustrator when LiveTrace hasn't done the trick, but recently tried www.vectormagic.com because I heard all of the accolades. The praise is well deserved. It's a time-saver & the end result is clean, crisp vector art. There is no desktop application available yet because they're waiting on a patent, so currently you upload a raster image and you'll get vector art in minutes. Cool site!