I've owned:
Diamond Rio PMP 300 SE (woot old school) http://en.wikipedia.org/wiki/Rio_PMP300
SonicBlue (basically what is now iRiver and was diamond MM) Rio Volt: http://www.amazon.com/RioVolt-Portab.../dp/B00005A1KZ
And now I have a 3rd gen 15GB iPod.

I doubt anyone one has anything older than the Rio PMP 300 tho :-> (MP3Man blew :-P)