Say what you will about it, but over the years World of Warcraft has had some fantastic boss battles. Fights like Shade of Aran were extremely fun at the time. Hell, that one in particular even got it's own gregorian chant it was so memorable! Kael'Thas even blew up the room you were fighting in, very cinematic.
Now if only you didn't end up doing them dozens of times till the charm is gone and all you want to do it curl into a fetal position and cry after some idiotic pug moved during the Flame Wreath when all you want is your loots.