Loved Cataclysm one the most. It was epic to see in-game zones such as Stranglethorn and 1k needles in good quality graphics.
Aelmai Frost/Blood DK
[A] Sargeras -US
Siege of Orgrimmar - 9/14 HM
Watching all the cinematic, which I do often enough, that first one is the one that makes me want to play the game the most. That first one is about exploration, which is what I come to mmos for.
Cataclysm has to be the worst.
Wrath. Still to date the best story line in any version of the game. I started in late Vanilla, a couple months before TBC's release. I remember leveling in the plaguelands and dealing with scourge everywhere. It invoked the nostalgia of Vanilla and made me really look forward to what was coming. I really, really, really hope the storyline in 6.0 will be as epic as Wrath's was.
WOTLK, loved when they put it in the commercial
WotLK was the best, no doubt. It is truly a piece of art!
I liked them all almost equally, but if I had to make a list
I'd say WotLK > Vanilla > MoP > Cata/TBC (cannot decide between these two, both epic)
I just went and watched all the patch cinematics for Vanilla WoW. BWL, Gates of Ahn'Qiraj, Naxxramas.. Oh, the memories.
It's honestly a toss up between MoP and Wrath for me. I voted MoP but god it's such a tough choice because the whole wrath expansion and coming from being a huge WC3 fan..... yeah I might change my vote to Wrath if I could. I loved the MoP character expressions and overall storyline though. Okay, yeah, Wrath wins by a little but I already voted lol.
WotlK, closley followed by MoP.
With thanks to Mnaaucici for the great sig
Wrath of the Lich King. The fact alone that it was centered around Warcraft's best villain takes it to its own level, but Terenas' narration truly did it for me. Raising Sindragosa was also an epic scene. Music could have not been better and always gives me chills.
Mists of Pandaria. It felt like a decently story-driven cinematic with a fair amount of action as well. Maybe a bit too light-hearted in a couple of scenes, which I'm not sure if I like or not, but overall I wouldn't say that bothered me too much. With all the amazing scenery, this was visually the most pleasing cinematic for me. Music was great as always.
Cataclysm. While it's just a action-packed cinematic with chaos, destruction and explosions and a bland villain giving a generic evil monologue, it at least showed an important lore event instead of just random battle sequences. Seeing all those familiar locations in the cinematic was definitely nice. It was even exciting at times, I'd say, and the music didn't fail to deliver.
The Burning Crusade. Well, sure you had Illidan uttering a few sentences (including his favourite line of course), but other than that it felt rather random. I'd rather see actual lore characters than just some nameless dudes fighting in a series of disconnected battle scenes. Though it did look good aesthetically, and once again the music worked.
Vanilla. Nostalgia aside, I think it felt rather meh. Very much like Burning Crusade, but this time we didn't have a major lore character involved in the cinematic or even any speech, aside from that anonymous narrator. Still looked good visually.