Jamba: I could not MB without it

Questhelper: lets me easily see who still needs what and points to the next quest when used with

Tomtom: crazy taxi style arrow and coordinate block

MobMap: nice addon full of info

Pitbull: nice unit frames addon when combined with

Clique: Pitbull + clique together is much better than healbot imo

Auctioneer: everyone has this right?

Engbags: Very configurable awesome sorting bag mod

Automaton: I think I am phasing this out with Jamba growing so nicely, but automates simple things like duel refusals and autorepair

Bartender 3: Button mod, very nice

Modality: With bartender lets you do some neat things with macros

Atlas and all atlas loot: Maps of instances and instance quests and all loot in one handy interface.

Smartbuff: one key smart buffing with all 5 toons sweetness

Gatherer: locate those mining/herbalism nodes

There are many others that sit deactivated on my accounts as they were replaced by these.