WowAce

Heads-up minimap display

Dims action buttons.

Mutes various chat related annoyances while in capital cities and instances.

Babble-2.2

Adds Archaeology items to AdiBags virtual groups

Litmus

Necronomicon2

Shows Status Bars that you can drag around and group up for your cooldowns

Adds manabars to the sides of Grid frames.

Cryolysis 2

Keeps track of your current location.

Mining data for Ackis Recipe List.

Highly-configurable shield / absorb tracker.

Enhancer

Reduces interface tedium by doing the little things for you.

AltClick an item in your bag to add it a mail, auction, or trade frame, and alt-click to buy a stack if reagents.

Displays classes and specialisation dependent stat priorities provided by icy-veins.com

Manufac

Omnibus

Displays Pet Info for Hunters and Warlocks. Also keeps track of Stables and Pet and Demon skills.