The long running Wowhead site has a Classic variant of their site, including era relevant comments, talent calculators, and more.
Classic WoW Resources
Leveling guides, spec recommendations, min/max ranking of class/spec combos for PvE/PvP, and more
Comprehensive list of available hunter pets along with their stats and abilities.
An excellent page that allows to to quickly see how dungeon and raid set armor looks like for your chosen class/race.