Karazhan, the harpsichord always brings a smile to my face :)
The Well of Eternity from Hour of Twilight, just loved the Idea to go back in the past and get to see a major lore event in-game!
Kara for sure, followed by Ulduar
Karazan was my favorite! It was so detailed and done right. I hope they update it someday!
My favorite instance is Icecrown Citadel. I love the music and the overall feel of the instance; I also love how everything is so blue!
I love Firelands, the druids, the things on fire, Ragnaros, Cenarius, oh god I love that raid so much
Halls of Lightning
My favorite instance is Blackrock Foundry, because I have been playing since Cata, and never capped until Mists, then the hardest raid difficulty I got to was Flex SoO, and now that I'm level 100, BrF was my first raid on a real difficulty (I ran it on heroic with 648 ilvl and died a lot).
I like the dungeon Maraudon. The best Raid is still and probably always will be Karazhan, with all of it's unique bosses,transmog drops, the music, pet drops. So much fun even though Attumens mount STILL hasn't dropped, and I've done it over a hundred times since it's first release...but still love it.
I have to be honest about loving ICC. I just really loved the way things were designed and when I first entered with my DK ready to kill bosses, I was surprised to find a buff was given to everyone. The hardness of the boss fight was amazing and it was one of my first real raiding experiences. ICC all the way man.
Hmm, I guess I'll go with Grim Batol. It was really cool to finally see an incarnation of it in game.
My Favourite Dungeon is Deadmines :)
My favorite instance is Karazhan! =)
the best Karazhan, Halls of Reflection and old Sunken Temple
I would have to say the scarlet monastery is my favorite, so much interesting stuff to see there.
My favourite instance.. mhmm.. I guess that would be Magister's Terrace. Least favourite (just for the record) Grimrail Depot....
My favorite instance is Karazhan.
Ulduar, by miles over any other instance
SoO, both love and hate, it was the first raid I ran with a group.