I tend to create a number of charcters and until I discovered mods, I had to crawl through the tutorial dungeon many, many times.  Entire lines of dialog are burned into my brain.  "It's you!  The one from my dreams!"  Or "Come closer, I prefer not have to shout."  Now I use an alternative start mod that postpones the tutorial dungeon.  
But as much as I am tired of the tutorial dungeon, I am freakin' annoyed to tears by the Mages Guild recommendation questline.  I can't even bring myself to rush through them, and so my characters tend to wander a bit, aimless, until they finish them.  I play by a rule that I cannot use any mod that adds spell/enchantment alters until I've completed the recommenation quests.
I still like the main quest, but delivering the amulet is getting old.  I find I do the Kvatch quests a lot later, now that I play FCOM.  Too hard to do it early.
Anyway ...
@ Arcadian:  I have a different slightly different problem.  I play the same characters: Nords/Bretons/Bosmers.  I play the same classes: Shieldmaidens, Valkyries/Witches Gypses/Marksmen Warriors.  I noticed this Spring that the game is feeling a little stale for me.  I need something new ...
@ Zhar: I had the same feeling.  I was like, okay, what next?  So I delivered the Amulet.  Then I started to Kvatch, but got distracted by the Killing Fields quest - which promptly killed me.  Maybe I'm svcker for punishment, but from then on I was hooked.
@ schmoe:  OMG, I forgot about the Gates ... added to list!  I try to ignore them, to pretend I don't actually see them.  Then the daedra pour out and start killing guards and I feel bad.  Fine.  Another gate to close.  
@ Jon Jern:  My admission - I've never actually completed either the Theives Guild or the Dark Brotherhood.  Maybe once, a long time ago.  Wow, I should actually create a character to do just that.
~ Dani ~ 
 Edit: @ Tamalak.  I love it!  Or: "Everyone's talking about the Hero of Kvatch!"  The first 200 times, it just kind of rolls off the tongue.  Then it starts grating on my nerves.