I absolutely love SM in its original form. Graveyard having lower level requirements as Cathedral for example makes it relevant for quite a level range. Being near to UC was also a big plus as a Horde player.
I cannot count all the Hunters, Shamans, Warriors I leveled in Vanilla with the sole purpose of equiping them with the whole SM mail items, Ravager even if some items were not "optimal" or simply exchanged a few levels later (I am looking at you Carpace of Tuten'kash and Icemetal Barbute).
Edit: Damn wrong thread
Gnomeregan. As much as I love gnomes, the city is not pretty and the bosses are forgettable.
what do you mean you dont like maraudon? You mean you dont like accidentally slipping off a bridge and losing 30 minutes of progress?
Mauradon is like the strict father of WC. Kids today will never know what its like spending 8 hours sitting down on a video game with four other miserable people and walking away with 2 mediocre greens
I'm gonna have to say Gnomeregan like many others here. It's just, I don't know, I've never had any love for it, but I don't hate it either. I think it's because it's confusing and takes awhile to get done, but mostly for me there wasn't much great loot there, and I don't fancy the visual design.
That said, I don't hate any vanilla dungeons, I just don't love it.
Gnomer with Ulda in a close 2nd!
Sunken Temple. At least if its a full run. You can almost never keep a group together for the full length.