I have a wonderful Cowon iAudio X5 with 30GBs running Rockbox. Sound is great, radio works,
etc. But I'm now selling it on a certain auction site (your chance, three days left, hint,
hint). Mainly, because I'm not totally satisfied with the feature set of Rockbox. E.g. it is
not able to handle more than one genre per track. Implementing such features is (for me) much
easier with Linux, so my next MP3-Player will be an N800 or an EEE PC. I'm just waiting for
32GB SD cards to become widely available under 300. So, if I would design a new audio player
(why MP3?, isn't that the bad version of Ogg Vorbis?), I would let it run Linux, not Rockbox,
just because this is where all the developers are.