A San Francisco-based music studio just launched a great sample and loop site: LoopBaby http://www.loopbaby.com
All the loops, tracks, and music on this site were made with Ableton Live. The site's a great example of what can be accomplished with Ableton.
LoopBaby features house, progressive trance, and techno beats available for instant download. I've already downloaded 3 tracks for my own demo tape and I'm starting to layer my vocals (I'll post my music soon ). I'd thought I'd share the link for any one looking for high-quality music.
Cheers!