Check out freshmeat.net for console mp3 players.
I use something called 'cmus'. It can play mp3, ogg, and possibly standard music cds. Not to mention it parses and remembers the id3 information on mp3's/etc for each session. I'm not too sure about input support with the program, it uses curses for the UI so it mostly limited to keyboard/keypad input. The dos usb stack looks interesting, but it probably will not work for an audio application such as what you wish to do. It seems to be a raw stack which would still require someone to develop a usb audio interface. Go with linux if you really need the usb audio, it has alsa/oss (which support usb audio) and a ****load of free audio apps.
The linux usb device site has your device listed as unsupported without firmware:
...however, searching the alsa-devel mailing list I found these: