Would a removable disk drive interface work?
No itunes. It opens on your computer as a removable disk with different folders. Music Video etc.
Drag and drop your shit into the music folder and you're done. Is that simple enough? File tree browsing (no browsing by Genre, Album, Artist). Just Folder(Artist)---> Subfolder(Album) ---> Files(Music Tracks)... HOWEVER... there's a custom firmware called rockbox... read the last part of my message for an explanation of why this rocks.
You get the picture. Very easy. No bullshit. As long as you don't just have a bunch of loose songs floating around all over.
I'd seriously go with an X5L.
30+ hour battery for the L version.
Top Tier sound quality. (Considered the best sounding of players still being manufactored, Rio Karma is considered #1)
20/30GB
FLAC/OGG/WMA/MP3/WAV Audio Support
FM Radio
Line In Recording
Radio Recording
Voice Recorder
MPEG4 video (15 FPS, meh. It plays video and the file sizes are tiny when you convert them down. Think of it as a bonus feature. Not good for feature length live action movies but great for cartoons like Futurama and The Simpsons.
USB On The Go
100% Absolutely bug fucking free firmware. The player won't give you shit.
Oh yeah...
It's also rockbox supported which makes you able to browse by ID3 tags, adds AC3 support (iirc?), gapless, improves battery life by increasing the efficiency of the player. Among many many MANY other things. Basically barring the limitations of the screen and 30gb capacity of the L series, Rockbox makes every MP3 player it touches nearly perfect. Also it lets you play games and shit on it. Jesus Christ, I'm looking right now and it adds a metric shitload of new cool little extras. It also makes it completely customizable.
Player feels really, really sturdy. Extremely resistant to scratches. Textured aluminum casing.
Player running normal firmware basically looks like this.


Review -
http://www.anythingbutipod.com/archives/2007/02/cowon-iaudio-x5-review.php