If your primary interest is in sampling new music, get a good MP3 player to match your ATH and relearn what good sound from good music should be.
MP3 players rated on sound quality,
http://www.anythingbutipod.com/archives/2008/12/top-5-mp3-players-of-2008.php
Note: If possible, get a player that can handle the lossless compression formats like, FLAC, OGG, etc. or use MP3's of at least 256kbps encoding quality.