We've already had it confirmed that earning the appreciation of NPC's will have some benefits, such as they may offer you a bed in their home if you break into their house during the night, rather than attacking you or demanding you leave. I'm wondering how deep these benefits will go. Oblivions "relationship" system was very shallow. Play a mini-game, increase a number, get information. That's it. It'd be nice if you could go for a drink with NPC's if their disposition was high enough, or other activities such as hunting, gambling, going to the arena (if there is one.) What the NPC likes doing would be specific to that NPC.
This could even have some significance in quests - if you're trying to ween information out of someone, you could take them to an Inn and get them drunk until they blurt out all their secrets. If you need someone dead, invite them on a hunt and "accidentally" kill them with a stray arrow, or lure them into a wolves den and leave them to the mercy of the wild dogs.
Let me know your thoughts!