ive beat every single guild-winterhold, thieves, companions, bard, dark brotherhood. ive also beat the civil war quest and of course the main quest. what else is there to do? is there some secret where i can just do something new?
For once I disagree with Orangenee (I probably just need to have a sit down and a chat with myself though).
I didn't do any "main" stuff after the 1st story dragon kill at all until I hit level 25 and even now at level 42 have only completed Mages.
There are hundreds of sidequests each that picks a random un-cleared dungeon for you to go to (for whatever reason). The reason ths is not such a worthless pursuit is simply because unlike Oblivion they're all hand designed and many are well worth the time.
I do agree though, you're unlikely to be too enthralled by "go fetch me missing book 17 for the library" or "kill Bandit Leader 147" but the fun is in the doing rather than the task itself (possibly).