WowAce

Says random things in chat when casting any spell or ability. Type "/ss help" for the user's manual.

Personal buff monitor - are you buff enough?

Better quest log and tracker

Provides a quick display for the LFG Call to Arms

Co-ordinated targetless Party and Raid wipe recovery. Evolved

NBuffBars

Keeps track of durability and pops up a dialog to repair when you go to a vendor who can.

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

A full package of auras for all 3 Shaman specializations

Display aura information inside action buttons

Adds achievement reminders to BigWigs

Displays information about the current zone on the World Map

Pins on the World Map for quests you have not completed yet

A FuBar plugin to show Recount.

Reports in raid chat whenever a raid member "fails." /EnsidiaFails to configure.

Role playing AddOn that shows extra information about characters as entered by the player.

Open all your mail

Searches bags/banks of all your characters/guilds.

MorgDKP

Simple quest item bar.