Favorite boss? Which and why?

Thought of starting this due to vent chatter.

Post your favorite bosses / encounters of the following below:

-Favorite Cata dungeon boss:

-Favorite Cata raid boss:

-Favorite dungeon boss all time:

-Favorite raid boss all time:

-Favorite Cata dungeon boss: Raptor boss in Zul Aman, simply for the chat during the fight when he kills people

-Favorite Cata raid boss: Twilight Council in BoT. It has lots of fun movements like moving INTO something bad to remove something bad. Getting certain debuffs like twin valkyr, always fun in a fight.

-Favorite dungeon boss all time: LK in Halls of Reflection, who doesn't like running away from an overpowered guy that wants to suck your soul??

-Favorite raid boss all time: Four Horsemen in Naxx (Wrath of the Lich King). First fight I took up healing as a proper role to down this guy. Enjoyed the healing aspect and switching aspect of this fight very very much.

The Curator from Karazhan. For some time the fight was all about mana management and I found the tactics and trial and error around that really fun. A bit later it was a cakewalk and no more fun.

-Favorite Cata dungeon boss: Usruk, Stonecore. I need to do some danceing

-Favorite Cata raid boss: Hard 1, i like the concil aswell, maloriak is fun to tank, Chimeron is fun to heal. But if you look away from the silly swimming in lava and get on a pillar (pillar design fail, if you ask me) fail on nefarian, that fight is very interesting and score high so far! I`ll vote Nefarian

Heigan the Unclean! Awesome!