Really into DJ-ing? Pacemaker's pocket-sized DJ lets you practice your song mixing skills on the wheels of molded plastic, all from the comfort of your own pants. The Pacemaker has a 120GB hard drive, USB 2.0 support, a touchpad, and various other DJ-ing functions (including loop-in, loop-out, re-loop, cue point search, and other things we have no idea about).
As for support, you can play back MP3, WAV, AAC, WMA, and FLAC. Not sure if this includes protected AAC from the iTunes store, however. Available this fall. Which means you can finally say there's party in your pants and everyone's invited—and mean it.
Product Page [Tonium]