Definitely Karazhan
Trial of the Champion!
The Corrupted Dreadwing. I shall have it. :D
Magister's terrace wasn't too bad for a dungeon...i enjyed it!
My favorite instance, to this day, would have to be Icecrown Citadel. It revealed a major plot point, had an amazing Alliance/Horde boss battle, and haunting music.
Karazhan with Ulduar as a close 2nd. Just spent so much time in these 2...
Karazhan is hands down my favorite, but Naxx and Icecrown Citadel were great as well.!
karazhan, always loved the haunted castle feel and the music in there is also really fitting :)
Stratholme: Main Gate! The appearance and feel of that place are very well done.
Shattered HallsThe loot looks awesome.
The Vortex Pinnacle, hands down. That instance is !@#$ing beautiful!
My favorite instance in WoW has got to be Wailing Caverns, just because I remember that being the first dungeon I ever did back in Vanilla.
that's an easy one! the pit of saron from good ol' wrath. i remember entering it with a rando group and no one knew tacts so we actually had to work them out ourselves. its actually one of my fondest wow memories, stickin it out in this new dungeon with a bunch of determined strangers!
Icecrown Citadel for life, I love it so much that it almost doesn't bother me the fact that I do it with my 6 toons every week for over a year and the mount never droped... almost, still love it though.
Mine is Blackrock Depths, just feels like how a dungeon should.
Not really have a favorite but if I have to pick. I guess Icecrown Citadel then.
I've always had a soft spot for Wailing Caverns. I think it was that my first character was a leatherworker and there was tons of it to skin. I also was a fan of Barrens chat.
hmm, I can't really say just one, so I'll say Siege of Orgrimmar and Black Temple
My favorite instance is and always will be Upper Blackrock. I like the pace and the loot. Great transmog stuff.
I ran AQ40 a lot for transmog gear, so I'd say that's my favorite.