Jag,
I don't use the watch to listen to mp3s. It makes a fine stealth 256MB flash drive
. Seriously, it doesn't interface with iTunes, so I couldn't use it for that.
If I need to listen to mp3s, I have an iPod Photo 40GB for that purpose. At least there I can carry more than a couple hours of music.
I am considering an iPod Shuffle for the gym though.
Mitch