Another difference is software packages. IIRC, there's three different SBLive!s. XGamer, MP3+, and Platinum (current versions are 5.1). XGamer and MP3+ are designed for the user on a budget. XGamer has a few games, and MP3+ has some various sound software packages. Platinum has most of the software of the other two, plus some extras, and, like Dagsverre said, a tray that goes on the front of your PC. The tray has all kinds of ports, you can even hook up an instrument to it (i.e. a keyboard).