Horrorwind's soundtrack sounds like movie music... It put me too sleep with it's overall lack of focus on rhythm, percussion and melody, 3 things very important to videogame music.
Thats problem with videogame music now or days... it's beginning to sound more like movie scores. Videogame music is completely different from movie scores!
The music in Morrowind is... Ambient music, it is not suppose to be noticeable, it is basically there to stop your ears from getting bored. The game makes use of sound effects such as wild animals/people in towns, the weather and so on to build up an atmosphere, the music in the game is not used for this purpose.
"Video game" music as you call it is called incidental music, which is also used in movies and TV shows. It's purpose is the opposite of ambience music, it is designed to add to the atmosphere and overall feeling of a scene (go and watch a horror movie or play a horror game, it wont even be half as scary without the sound turned on, much the same, a sad scene in a film/movie wont do much without that music you hear in the background).
Anyway.
Morrowind:
CLIFF RACERS
"We're watching you scum!"
Jumping like a mother fucker on steroids
(seriously, a large, detailed world with a lot to explore and tons to do, even plain NPCs have tons to say, but the gameplay and graphics suck)
Oblivion
"I saw a mudcrab the other day!"
(serious answer, less depth to everything, a boring world not worth exploring but the gameplay and graphics are much better)
Both of them:
Filled with bugs
Horribly unbalanced. You might get 27 skills or whatever, but only 3 (4 in oblivion) are useful, long sword, heavy armor, marksman (and stealth in Oblivion, Stealth is way overpowered, even the stealth quests are. Do a Dark Brotherhood quest, get a god slayer sword +10, a cool immortal horse and an awesome looking robe and set of armor, do a mages guild quest, IF you get anything it is a plain robe with no effects at all, it doesn't even look good!).
Magic in both games is dull and basically useless, a single sword swing is more powerful by far with the right stats and an enchanted sword. Even debuffing abilities work best when enchanted on a weapon (you either cast 2 of these spells then run out of mana and have to hunt for rare potions to heal it, or enchant the exact same effect on a weapon, which will last for a good hundred of so hits and can easily be recharged... I know which one I would do!)
I personally prefer Morrowind. The gameplay might not be as good, and the character models are ugly as fuck, but it has so much more depth and things to do, I played it for over 100 hours and still had a ton of stuff to do, compared to Oblivion where I'd basically done everything in 40 hours.