I'd go for the iRiver H340 or IHP-140. It plays MP3, WMA, ASF, WAV, and OGG music files. It also has an FM tuner and voice recorder. My little brother has an IHP-120 and it has incredible sound quality and battery life. The nicest thing about it is that you just plug it in and it is seen right away as a portable hd, you can just drag and drop files to/from it w/o an special drivers or software. the zen and ipod reqire their proprietary software to load/remove audio from the player.
<A HREF="http://www.folken.net/myrig.htm" target="_new">My precious...</A>