The fact that Chris Carter would’ve been excited to have REM agree to having their song on an Album for a then 2 (3?) year old show?
I cant find my CD case at the moment, but Im pretty sure that on the liner notes Carter explains that the music on the original s/track (Songs in the Key of X) are the ones that were either influential in the the tone of the series and/or ones that the writers enjoyed listening to, most of them eventually ended up in the series or movie (ie Red Right Hand for Duane Barry/Ascension, Hands of Death for the episode with Jack Black/Giovanni Ribsani(sp?)).
Catatonias Mulder and Scully fits in with neither IMO, * Me Kitten probably should’ve been one of the 3 hidden tracks rather than #5, and move one of the Nick Cave ones to 5.
I second this, though the fact that you have a mix of composers (Fiedel, Howard, Isham, Kamen, Mancina, Shaiman, etc.) may have had something to do with it…