I just had a thought today, in the bathroom, where I have most of my good thoughts.
When the iPod was released, I bemoaned that it had no wireless connectivity. But now that iTunes will have Rendezvous capability -- share your playlists with any other Mac on the LAN, automatically -- I wonder if a wireless iPod isn't around the corner.
Imagine, having an iPod that just automatically picked up the playlists in the general vicinity. It's a new form of wardriving: walk around the city and steal^Wlisten to other people's music!