i played through oblivion once and the only way i could handle going back for more was after installing some mods
you know the main things that irked me?
1. the voice acting - i'd rather no VA at all for minor npc's rather than heading into a store and talking to Generic Breton Voice 2 for the 50th ****ing time
2. the mages guild quests
it's the fricken MAGES guild, yet once you get past the (dull) recommendation quests, all the quests read the same - go to this dungeon, kill people, retrieve item - ad nauseum
i'd expect crap like that with the fighters guild, not the mages guild - at least the morrowind mages guild had you doing some actual mage-relevant quests!