World of Warcraft/Blizz

Battle Net - Blizzards Official account site

Curse - Hosts downloadable add-ons for WoW.

MMO-Champion - Info on gear, items, and stuff.

WoW head - Info for everything EVERYTHING WoW

WoWpedia - Encyclopedia for all things WoW

WoW Official Page - View character / items in game.

Professions, Gear, Class

Icy Veins - Info on leveling any profession.

Best Profession GuidesVeins - Class guides, news for WoW.
Ask Mr Bot - Advanced gear optimization for WoW.

Wow Professions - A guide for power leveling professions.
WoW Popular - Builds, glyphs, gems, enchants, and gear.