I wanted to propose a slightly bloodthirsty Breakfast Topic -- Favorite PvP kill. I guess you could do cool PvE kills, too. There have been some hilarious defeats of both types that I reveled in, and that still crack me up to this day. Specifically, an Alliance mage had been taunting us in Wintergrasp from on top of the fort just after the battle. So I took my DK up, began to fall, and deathgripped him down into the courtyard full of Horde. We both lost a lot of hit points in that fall, and at first the other Horde were wondering why I'd dropped my self so far... then they ate him.
One of my favorites was out in the world, on a raid on Thunder Bluff. I, on my shaman, had been beaten down to low health by a trio of Horde melee, and a shadow priest came to my aid, standing on a roof. Between us, the priest and I took two down, but the third had almost got me. As I popped my Spiritwalker's Grace to cast a Lava Burst, the priest gripped me, resulting in a bizarre spectacle where my ball of fire and I seemed to part company in mid-air, me flying up onto the roof, and it flying into the hapless warrior, killing him. It looked really cool!
So tell me your stories, they don't have to be PvP, could be dungeon bosses, raid bosses, quest mobs, trash, anything you like.