WowAce

EquipmentManager_SwapSpecs

Yes, I really want to destroy that item, stop asking.

Guild members

Smoothly fade from black after loading screens

Stop Peggle from spamming you.

Steroids

oUF Layout

FBP2SlideBar

With Mists of Pandaria Blizzard publish all characters from an account unless you disable that 'feature'. This addon warns you.

ABFu

Adds HTML output to Ouro Loot

A mod to filter the Trade chat, shunting it to a seperate chat window if it exists (chat window is OMGWTFBBQ).

Nostalgia

Relays item drops to your guild chat.

TaintChecker

LDB port of TimeToDie, showing estimated target life expectancy in an LDB object

Automates sending/accepting group invites in several different situations.

Allows custom Combat Log filtering

GBS tricks other addons into thinking a guild bank is your personal bank.

Tells you which nest to fly to