One thing that Bethesda games have all missed, is the feeling of friendship. In all of their games, there isn't any NPC's you feel like you've truly developed a relationship with..
That is such a good point! I think that's one of the things that makes their games feel "gamey". Everything revolves around you.
Anyway, Morrowind is one of my favorite games of all time, warts and all so it got my vote. Together with Tribunal and Bloodmoon, it just makes for a still impressive gameworld and experience.
However, I have to mention that I may be changing my opinion of Oblivion. I've hated it for a long time but recently picked it up for the 360 and am actually enjoying it. It's no Morrowind, not even close, but after deciding to ignore the voice acting, some of the dialogue, all the hand holding and the level scaling, I have to say the majority of quests (aside from the main quest) are pretty entertaining.
I guess I have certain expectations when I play a PC RPG and playing this on the 360 I just lowered my genre expectations and am thinking of it as an action/adventure with RPG elements instead of a hardcore RPG. It's a good couch game: playing it on my 42" LCD with the 5.1 sound cranked up, it can get immersive at times.
I still managed to get a little bored in between quests though, the world is nowhere as fascinating to explore as Morrowind but I have to say quests in general are improved greatlyfrom Morrowind and I just had to give it another chance to discover that aspect.
And from the short time I spent with Daggerfall, I would say Oblivion feels more like it than Morrowind.