Skyrim soundtrack... why would I want to listen to anything else...
Because the 5 songs for each Wilderness/Town/Dungeon get boring after the first 100 hours.
I'll add my whole Morrowind folder, which includes a number of songs from the Conan soundtrack, a lot of tracks from the Realms of Arcania series, and even the love-theme from Star Wars Ep2. It fits so well, that I can't watch the movie without images of a hike along the Bitter Coast forming in my mind.
If I could add just one track, then I'd choose the Morrowind theme.