I like the Dark Brotherhood main quest and Civil War Stormcloaks quesline.

They are fun to play over and over again.

I like the Thieves Guild and the Civil War questlines.

Thieves Guild and the Dawngaurd questline- mainly for the

I always enjoy the Daedric quests, never tire of them irrespective of which character I'm playing.

The Dark Brotherhood, just because you can take out your targets in so many different ways.

Naming the quest is fine, telling why is a spoiler.

Definitely Dark Brotherhood, I hate killing the Emperor but I do him justice by killing that spoiled brat rich boy who gives you the contract. I love doing The Forsworn Conspiracy also, because it's pretty quick and has a lot of interesting twists.

I enjoy the Dark Brotherhood, like another user said, you have variety when you make your kills.

I hate the TG. Way to long, especially when you have to get them back on your feet. I mainly do it for the paying the bounty off. Much cheaper.

I'm doing my second runthrough of Skyrim right now. The only questline I've done is the College, which was worse than I remembered. I am enjoying the Daedric Quests on their second round, though, so they get the nomination from me.

I've honestly have gotten bored of all the faction/guild quest lines.. i guess if you do them enough times right after another on multiple characters within the period of a month, you'll eventually get bored of them.

but i now like the random side quests, no particular ones though... just all of them.

Daedric quests never get boring, nor does The Dark Brotherhood questline.

There's several I like even though they're too short or fall short of full potential but I can't elaborate on the reasons without spoiling.

I like the companions even though I dislike being forced to accept something to contiue

I like the civil war stormcloaks side...viva la revolucion

I like some of the MQ, especially the place that we visit only once even though it is somewhat bare, the epic music makes my day

the list goes on and on

I've only gotten bored with the companions, probably because it is so short. The other questlines still keep my attention pretty well.

Dark brotherhood questline, so i can play the darkbrotherhood resurrection part 1 questline after it(mod).

Civil war. There is nothing really keeping me from doing it, unless if i RP a passive guy.

Dark Brotherhood, Dawnguard, and the Daedic quests.