WowAce

Protractor

A module that lets you find out what today's dailies are without having to visit the quest givers.

LFD status via a DataBroker display rather than the minimap.

FuBar_DPS

A simple addon that warns you if your pet isn't attacking while you're in combat.

Hitman

Angry Boss Reminders helps raiders switch to the proper talents, glyphs, and gear for each boss during a raid.

Reverse Engineering will drill down and search your tradeskills for their elements

Makes grid QuickHealth aware

TableTopLib

EyeCandy

Auto sizes frame layout depending on group/raid size or predefined zone data

Shows Chat as Combat Text

A popup menu containing user-programmable scripts.

FelwoodFarmer

Show coordinates on minimap

Automatically invites player from templates.

KC_Mobility

InstanceMaps

TradeBar