I rarely listen to anything other than the original music when I play
Morrowind. It's become such an intrinsic part of the game for me, and I never get tired of it. Ever since installing a bunch of ambient sound effect mods, I've spent most of the time playing without any music at all. These sound mods combined with a few lighting mods to make the nights realistically dark make for a pretty incredible experience exploring the wilderness.
I have occasionally added some of the
Daggerfall tracks, and like everybody else, the LOTR soundtrack.