Thottbot
Database for quests, mobs, spells/abilities, maps, items and more, being constantly updated through players transmitting data from an in-game interface

WoWWiki
Online World of Warcraft encyclopedia updated by the community.

WorldofWar
Community Site with News, Mods, Databases, Items, Quests, Maps, Professions, Strategies, Trading, Forums and Files.

Warcry
Contains news, screenshots, game information and forums.

World of Warcraft Guru
The largest international WoW database for Quests, Items, Spells, Zones, NPCs, Maps, and more.

World of Warcraft Stratics
One of the best sources for rumors....I mean news.

Warcraft Movies
Contains a large database of movies created using World of Warcraft.

IGN's Wow Vault
Everything you could want in a fansite including news, talent calculators, media, community database, guides, maps, and forums.

WoW Myspace
The official Myspace page for world of warcraft.

Blizzard Entertainment
The official website of Blizzard Entertainment, the company responsible for creating and maintaining World of Warcraft.

World of Warcraft Radio
This is an internet radio show run by some WoW players over in Europe. They have been featured on the wow hompage. I recommend Total Buscuit. He is fun to listen to.

WoWStatus
For those interested in this sort of thing, this is the main hub for info on privately run WoW servers.

The Goblin Workshop
The Goblin Workshop is a complete guide to World of Warcraft, featuring a gigantic database of quest spoilers, monsters and NPCs. If you cant find what you need on those other database sites, try this one.

Wow Blue Tracker
The World of Warcraft Blue Tracker collects official Blizzard (Blue) Posts and archives them. Best place by far to specifically track forum posts by Blizzard community managers.