All you need to be able get XMMS up and running in Intrepid (or Hardy), incl. FLAC, WMA, mp4, can be found in this zipped file.
UPDATE: THE LIBFAAD/M4A/MP4/AAC DIDN’T COMPILE (SOURCE IN THE ZIP) AND I COULDN’T SOLVE THE ISSUE, BUT THEN – AHA!! – I FOUND A .DEB HERE AND IT WORKS IN INTREPID:
If you need information about how to use it, look here, here, and here. So now I have XMMS running in Intrepid with all needed plugins – wouldn’t it just be nice if the olden golden player came back into the repos?