Link to the things I use.
(Used to be just macros but I don't know how to rename the page. :P)
http://wowupgrade.com/ Checks your character from the Armory and tells you what would be best suited to an upgrade. (NOTE: Upgrades are going away at least temporarily in 5.2. And the site only works for DPS at the moment. (1/17/13)
http://www.noxxic.com/ Shows you stat priorities, rotations, etc for all the classes and specs. Askmrrobot is a secondary site but has some stupid ideas, preferring a strength based weapon (ONLY 1:1 attack power) to a lower itemlevel but much better itemized agility based weapon for a cat druid.