Where this is going (Score 1)

The missing piece -- as others have pointed out -- is a roaming display for adjusting songs on the fly. A wi-fi enabled iPod seems likely (if they can overcome the battery drain). But wi-fi enabled iPods are overkill if marketed only for this type of application. Putting wi-fi on an iPod just for music sharing (a very restricted application) is a very high cost to pay (manufacturing). Apple may be reticent to take this approach without also leveraging that expense by providing other PDA-ish behaviors on the iPod (web clipping, email access, etc ...). If they can't overcome that marketing barrier (who wants to pay that much for an iPod that can't do other wi-fi'ish things?), they may just leave the market alone until they can. Apple's own (unannounced) initiatives in this area aside -- I'll bet we see more than one announcement by the end of the week for PDA software designed to use your wi-fi enabled PDA to control the Express.