Mind control. THE BEST DUNGEON CC EVAR.

[Aqua]

Yeah we used it in Dead Mines and it Rocked da howse. Bring a priest to everything!

[Siri]

I was planning to write a mini-guide on Mind Control, used right and on specific mobs it can be absolutely ludicrous.
For example, the tempest witches in Throne of the Tides have a chain lightning that hits for 40k on each target, if you can hit 3 (possible on two packs in the instance) you can rock ~60k dps.
The Squallshapers in Deadmines have an ability that bounces, it causes 20k damage on the first target, 40k on the second and 80k on the third, it's a 3 second cast.

There's other good examples and other good uses of MC, not just dealing damage.