1st Gen 5GB: Was my first main iPod, then became my work iPod, then became mostly a nostalgia piece.
2nd Gen 20GB: Was my main iPod. Sold it after winning a 3rd Gen in a contest.
3rd Gen 10GB: Was my main iPod, now my work iPod. Won in an AOL beta contest. Don't really care for the button layout, but it was free.
5th Gen 60GB: Current main iPod. Black model.
The title of "work iPod" is for the iPod that I use to keep only the songs of the artists I've recently been working for. I work as a lighting designer for live concert tours, and it's quite handy to keep all of the artists music on one iPod.
So I currently have three: a 1st 5GB, a 3rd 10GB, and a 5th 60GB (black).