Wrath of the Lich King is my favorite and MoP comes as second, both because of the story.
My favorite expansion was Burning Crusade. I practically lived outside Black Temple to kill Illidan with my rogue :D
My favorite expansion is Wrath of the Lichking of course!
Wrath of the Lich King!
I started playing WoW in TBC but never hit level cap and missed out on WoTLK though I really enjoyed Ulduar and ICC when i finally did get to do them. In MoP ToT had some of the best bosses of all but i wasn't a fan of the questing and lack of dungeons after the first patch not to mention the fact that the dungeons were way to easy even in questing greens. So I have to say my favorite overall was Cata good story and zones, heroic dungeons were great especially the HoT set, was slightly disappointed with DS after Firelands but all in all a good expansion.
Wrath was by far my favorite expansion, it was the xpac that I started raiding in and it was the only one that I maxed all the reps for :)
My favorite expansion was Wrath of the lich king i loved its raids and i loved the atmosphere of northrend but the thing i loved most about it was the music
Mists of Pandaria. I loved Wrath and I feel that Mists took all the good stuff from Wrath and built upon it.
I definitely liked Wrath the best. All the classic feel of original WoW without being completely impossibly hard.
I still haven't even bought the new expansion so this would be sweet
The burning crusade, simply because of the people i played with.
It would be The Burning Crusade, first to see an PVP arena and the first time I tried PVP for real and since then I have never stopped doing PVP and still will, PVP have really let me experience a lot of fun, stress, happy and sad moments and this is really what makes WoW what it is, these memories with my friends is something that never goes away, still today even so many years after the expansion me and my friends still talking about the old days and how we never can't let go of it :) so if it wasn't because of the arena I might not have enjoyed the PVP aspect of the game as I do now and I might now have experienced all the fun and crazy moments with my friends, So I really thank blizzard to have added this to the expansion! :)
WotLK. Bringing a conclusion to a sad tale.
Mists for sure. I loved the environment, and the themes of the story, especially how we were literally fighting our own inner flaws. Also really loved the aesthetics, and the destruction of the Vale. good stuff.
Cata because was the expansion that i started to play
Mists of Pandaria! It introduced me to the game with it's Eastern influence, which I have to say is the only reason I pushed through what I initially thought was a bad game. Sure, there were all sorts of issues, and the older content seems like it would have been more fun at the time, but this expansion was the most accessible in my opinion, and its influence is the reason I'm here today. Not enough money to buy WoD, so fingers crossed! ^_^
I started playing during TBC but didn't do much during the expansion, but Wrath was a whole new story, from lore to mechanics, from questing to raiding this was my favorite expansion, especially during Ulduar.
(Sorry for my bad english! >.<)My favorite expansion is Mits of Pandaria. It's so well decorated that left everything to that oriental touch. Lore impeccable <3. New dynamic dungeon giving many more options than before.For me it was the best of times.
My favorite expansion was Wrath of the Lich King. Been playing since vanilla but the death knight class captured me along with all the lore behind Arthas and the other characters of Warcraft.
I started just at the end of Cataclysm, so it's easy to say that Mists of Pandaria has been my favorite expansion so far. It's easy to see, though, how Northrend, Ulduar, and ICC captured the hearts of so many. I love being on that continent, myself.