With reference to the above posts......
Morrowind
Pros:-
Good caves for looting
More interesting story line
More skills and weapons
More quests
Levitation
Better Story
Vast environment
Great soundtrack
More skill choices
Cons:-
Depressing, empty landscape
Lifeless towns
Boring capital city.
A lot of tedious quests
Poor AI
No compass. (Some quests are really vague about where to go.)
Cliffracers
Morrowind is more of an RPG than an action game, so if you can't hit an enemy that is because your weapon skill and/or agility are to low/
Mainly text speech.
The game was never terribly accessible or instantly enthralling and it really hasn't aged well
Oblivion:
Pros:-
Better combat system
Better magic system
More lively towns
Interesting quests
Sneaking and learning NPC’s schedules
Horses
Better graphics
Better weather effects
Fast travel
Improved gameplay
Shivering Isle and Knights of the Nine DLC
Being able to join all the guilds!
Cons:-
Levelled monsters and loot
Guards with ESP!
The Lock Picking
The ‘getting somebody to like you’ mini game.
Poor main quest.
Oblivion was my favourite game ever...until....
Skyrim
I can't really comment too much on Skyrim because despite having now played for 65 hours, I have only completed The Companions quest line and I've only visited three towns and killed two dragons.
I think it is better than Oblivion and I can confidently predict it will be my top game for a long time. For me, it does everything right. I can pick it up for 15 minutes and explore a cave or 30 minutes and complete a quest line.
Other times I play for a couple of hours and really haven't done anything but explore.
With Infinite quests, DLC and Mods, this game could be the last one I ever purchase!
http://www.techspot.com/news/42852-bethesda-skyrim-finds-medium-between-morrowind-oblivion.html