Icecrown Citadel is my favourite :)
Well of Eternity. Man did I look good as a night elf rogue. The new style of architecture was also nice.
Kara rules them all.
"TIME FOR FUN!" in Shadow Labyrinth.
I haven't done many instances while leveling, so the instance i pick is fairly recent. I enjoy Shadowmoon Burial Grounds because of the purple color scheme, the dark evilness of the area, and the majestic magic feel of the dungeon. I originally hated this dungeon because lfd normal took 4-7 hours working with new players to defeat it. When everyone knew what they were doing in heroic, it became faster and more fun.
My favorite instance is sethekk halls. I worked hard for my flight form and got my lovely raven lord.
Raid: KarazhanDungeon: The Arcatraz
my favorite instance is siege of ogrimmar
I only did 5 mans and some Naxx/Ulduar back in 09, so my favorite was probably Azjol-Nerub! Currently in love with Blackrock Foundry though. Not necessarily because it's the best raid, but because it's the first raid tier I've done entirely with my guild, and getting Blackhand down a few nights ago was an incredible accomplishment :D
My favorite instance. That's a hard one. But if I that to choose one, it would properly be. the good one once. The once from vanilla . Liked those
My fav has to be Karazhan, first raid I every done. So much nostalgia. But mount shall never come... :(
My favourite instance would have to be ICC (Icecrown Citadel).
My fav was vanilla Molten Core. Always a pleasure downing Rags
As a draenei fan, WoD Auchindoun for the looks.
My favorite instance: Blackwing LairLast boss waiting for you sitting in the throne, epic !
I think my all time favourite has to be Blackrock Depths, I've done Blackrock Depths both at the appropriate level and insanely over levelled for various different reasons. It's just epic and a lot of fun!
"The End Time, I once called this place. I had not seen by then. I did not know. You hope to, what? Stop me here? Change the fate I worked so tirelessly to weave?" Even years after last doing that, I can still recite Murozond's lines almost by heart.
Favorite dungeon has to be Blackrock Depths. Favorate raid is Icecrown Citadel.