Bungie.net – The official way to check your stats. You can also equip weapons/armor and check your vault etc.
Destinystatus.com – A really well designed and informative site. Includes your equipped weapons/armor as well as ranks and marks.
destinyrep.com – A little less info than DestinyStatus but it has a focus on ranks over all else.
DestinyTracker.com – Perfect for Stats, Leaderboards, Progress, and Signatures.
Reddit Fireteams – My favorite route to a good fireteam.
DestinyLFG.net – Another efficient and well-populated site for finding a group.
DestinyLFG.com – I’ve personally never used this site but I’ve heard some good things about it recently.
Destinypickupgroups.com – Again, I’ve not used it but I’ve heard some good things.
DestinyTracker LFG – This shining light of Destiny resources also has its own LFG section. It looks well populated and I’ll certainly be giving it a try next time I need to raid.
Destiny Public Events – The best way to find public events in the game.
VoGloot.com – A breakdown of the Vault of Glass loot and where you can receive it.
Rare Fusion Rifles – Tells you if the gunsmith is selling Rare fusion rifles. You can also get it to email you a notification.
Destinygundamage.info – A utility to compare Destiny gun damage.
Grimoire Cards – An excellent way to check all of the Grimoire cards even if you haven’t achieved them yet.
IsXurAtTheTower.com – Lets you know if Xur is at the tower.