When the iPod debuted it only worked on a small percentage of the world's computers and had no media store. It grew into a winner, but the first gen wasn't particularly special.
The first-gen iPod had Firewire (instead of pre-2.0 USB), the scroll wheel (vs. button-only interfaces), and it actually fit in a shirt pocket (vs. the Jukebox which was the size of a portable CD player).