We should probably make this into a sticky of some sort just so we don't get a jumble of different posts about the same sites.
I would like to reccomend:
http://www.wowhead.com ;This is gives brilliant info on items/quests/talents etc
http://www.wow.com ;This is where I get all my WoW news!
I'd also like to say that wowwiki has more than just talents, it also has guides to nearly everything in the game from profession guides to raid guides.