[Damn, I need more categories or something.]
Someone mentioned this on Slashdot so I went to see if it was true. You can copy MP3s directly from one Nomad Jukebox 3 (or Nomad Zen) to another over FireWire. That's pretty cool. I know the FireWire spec was written to support device-to-device communications but you so rarely see it used. It does mention, however, that it won't transfer DRM'd WMA files. The Slashdot comment was in response to someone desiring iPod-to-iPod transfers and presumably if Apple made such a thing, they would have similar restrictions on DRM'd files.