Pre head-fi:
generic no name earbuds -> Aiwa earbuds -> iBuds
Post head-fi:
Shure e2c-> Koss Portapro -> Shure e3c
My iPod upgrades have been a bit more prolific though:
2nd gen 10GB -> 3rd gen 15GB -> 4th gen 20GB-> photo 20GB-> video 30GB
Luckily from the 3rd gen onward all iPod upgrades were through work (I worked part time selling Apple stuff...) with optional 99€ purchases whenever a newer model was released. So now all my friends have my old iPods
