I think they all have their own strengths and weaknesses.
I could never really get in Daggerfall myself, the huge world really appealed to me but I found various aspects really confusing if not badly designed. Like many other games it also suffered from being made in that awkward early 3D era.
Morrowind obviously has very dated combat, but the story and setting are awesome in my opinion. My first few days in Morrowind were some of the most immersive and memorable I've ever had in a game.
Oblivion? I honestly enjoyed it but I think it's the weakest in the series post-Daggerfall (which I haven't played enough to really judge). Off the top of my head, the only thing that stands out are the beautiful forests and soothing music. Everything else is better done in either Morrowind or Skyrim. I guess it could have a certain appeal as being the "middle of the road" game, but it didn't do it for me in the long run.
Skyrim is, I think, almost as much fun as Morrowind to explore but the storylines and quests are severly lacking. I also don't like the linear dungeon design.
If I had to pick one, it would be a toss between Morrowind and Skyrim. My heart says Morrowind but my brain says Skyrim.
Oblivion is my favourite by about a mile.
For some reason I don't enjoy Skyrim nearly as much.
Skyrim was dumbed down too much. The level system was as vanilla as it gets.
The inability to create spells was a major let-down for me as well.
The repetetive dragon battles got old fast
The different factions were all pretty terrible meaning I cared for none of them - which sucks.
The races have been reduced to mostly palette swaps. *yawn*
Overall: Skyrim is over-rated. It was okay, just not the be all end all game that people make it out to be.
OP: Morrowind (better world) or Oblivion (better combat)
Honestly, Skyrim is my least favorite Elder Scrolls Games, and by far the most over-rated of the series. I can't believe people would pit the best of the best like Morrowind against Skyrim, which only lasted about 9 hours to me. Story was horrible, gameplay was rehashed Fallout 3 with those finishers, no skill involved accept when aiming things, and the RPG elements were just terrible. I'm dumbfounded that Skyrim got as much praise at it did, but enough ranting for one comment.
Morrowind wins this by a long shot in my opinion. Meh combat doesn't break a game that just is that insanely addictive immersive and interesting. If you've made it this far in the thread, you obviously already know the rest of Morrowins Pros, so I'll shut up now.
Played in order: Daggerfall, Battlespire, Oblivion and Skyrim. Skyrim owns in everthing except for terror, that goes to Daggerfall with that dude screaming VENGEANCE all the damn time.. never did figure that out.
I'm honestly amazed people prefer Skyrim over Morrowind or even Oblivion. Skyrim just feels dea and soulless to me, with little or no character or depth. Everything boils down to "Go here/Kill Draugr/Find thing." The magic sucked balls. There were less enemy and equipment types. Sure, the gameplay was a bit better, but that's always been shit, and who played Morrowind for the combat?