Druids: Druid builds - WoWWiki - Your guide to the World of Warcraft (Many builds and loads of thoery)
Hunters: Hunter builds - WoWWiki - Your guide to the World of Warcraft (Loads of thoery and FAQ, also some build examples)
Mages: Mage builds - WoWWiki - Your guide to the World of Warcraft (Many useless builds, but all the good ones are there also, plus much theory)
Paladins: Paladin builds - WoWWiki - Your guide to the World of Warcraft (A good bunch of builds with indevidual theory, also a step by step how to place talent points up to level 50)
Priests: Priest builds - WoWWiki - Your guide to the World of Warcraft (Loads of builds and theory. Step how to place talent points up to level 70 and explanation on how to solo mobs and so on)
Rogue: Rogue builds - WoWWiki - Your guide to the World of Warcraft (MANY builds with individual theory, also a step by step how to place talent points up to level 60)
Shamman: Shaman builds - WoWWiki - Your guide to the World of Warcraft (only 13 builds but much theory and how the different talent trees help you in different situations)
ShammyWiKi » Enhancement Talent Builds
ShammyWiKi » Restoration Talent Builds
ShammyWiKi » Elemental Talent Builds
Warlock: Warlock builds - WoWWiki - Your guide to the World of Warcraft (Many builds and loads of thoery)
Warrior: Warrior builds - WoWWiki - Your guide to the World of Warcraft (Many builds and loads of thoery)