A bit of good news on this front.
A Korean firm called "Cowon" is producing a number of Players which, as well as mp3, wav and wma, also play back oggvorbis and even flac files. They are called "iAudio".
No fancy software is needed to load the files onto the player. As long as your "ripper" titles the files it produces in track order, that's how they run within each subfolder. You can use XMMS, Amarok, Kaffeine etc, to save playlist M3U files onto your unit, and someone has posted a script to turn the "slashes" and linebreaks to make them Windows-compatible - the only problem that Linux users are likely to have.
The sound quality is said to far exceed the iPod. The body of the 20Gb+ HDD players is real metallic Aluminium, not plastic in disguise, and it feels as solid as a rock.
Sites to take a look are
The latest one, the M5, is purely an audio player (no radio, piccies or video clips) and this is the one I am getting. There is a thicker version, the M5L, which has a larger battery inside, giving 30 hours playback instead of the standard 14.
The one with all the extras is the X5 or X5L
Finally, MISCO (http://www.misco.co.uk
) are doing very good prices on the M5L and X5L.
I know this is a bit of a gushing advert, but in these days of iPod and iRiver with their proprietory formats, it is refreshing to see a simple HDD music player with simple file management and open systems available.