If you haven't played Morrowind, I recommend you do so. It gives you a break from all the required quests in usual RPGs and you could just do whatever you darn well please in either of the three.
I doubt you will be able to play ESII Daggerfall, since it's an old game and all, so it would need a very old computer system, but you will be satisfied and more if you play either Oblivion or Morrowind. Oblivion is ok, but it lacks "variety", Morrowind has PLENTY of variety, message me for reasons...