Just my two-penneth here :-)
For any caster, I'd recommend Coolline to track CDs - it's compact and doesn't break^^
For hunters, Autotrack is not smart - it can throw in a delay when you really don't want it, and the way Improved tracking works now, you'll be getting your damage bonus unless you start tracking Hidden targets.
Top of the list of addons I could not exist without would have to be Opie - you, too, can have 50 spells bound to 5 buttons, should you so want^^