The WoW Armory has a dedicated Firsts page that shows world first for acheivments.
If you do a search for a specific realm you can find the first for just that realm.
Ekn was first for Grand Master Engineer!
Adenrei got the tri-fecta of Realm First Level 80, Realm First Level 80 Shaman, and Realm First Level 80 Draeni!
Gratz again, and Gratz to Ekn!
"Your a Frost Mage... and you wanna raid?!?! Why don't you just PVP alot?" - Some guy in Shatt