shaman.. all the others are boring as fuck. take my word, warlock is the most annoying thing to level because life tapping every 2 seconds for mana and repeat drain life seems more like a chore than a fun leveling experience. mage is pew pew, drink drink. rogue, nuff said, u attack, run vanish, bandage and hope to kill that same mob... this time.
shaman, heal, gg damage. ya do it pussy