it's the interface, i dont want to be fiddling around with a crappy interface if i want to change playlists, every other player i have has had a crap screen and a rubbish gui, also the size of the things, the ipod is smaller than most players, also other players feel flimsy, my friends creative player is all horribly plasticy and flimsy.
if your a mac user or will be in the future no question get an ipod, if your a pc user and dont intend to be a mac user i'd still get an ipod it's just such a nice player. and no i dont fall for the hype and popularity of the ipod i have a first gen 5GB ipod aswell as my 20GB 3rd gen.