WowAce

Monitors AP when dots are applied, clearly showing current vs applied AP levels.

Enables cooldown notification between players and allows party members access to each-others spell books.

Prospecting and Disenchanting Aide

vChat

Adds item values to chat messages.

Calendar improvements

Objective Tracker

Dynamically atering layout in raid environment (Tanks, Ranged / Melee DPS, Healers)

Generate a macro with random mounts

Crowd-control monitor

Draws some lovely 3D portraits in the standard Blizzard artwork.

BigTrouble

Open those clams (and other containers)

Displays online friends.

Assistance to the dance during Dread Spray

A frame with a text that gives you the amount absorb left on target, or in TankMode absorbs left on yourself.

NiHao

On login, displays changes to your guild since the last time you logged in.

TalentShow-1.0

Fancy up the ExtraActionButton frame