[Yumyums Inmahtumtums]

Druid/warrior is extremely viable for agro kiting (make sure warrior is Zerked for maximum results).

Druid/enchanter is an incredibly powerful outdoor combo because of snare and heals. The argument can be made for shaman but that would better suit indoor dungeons. Heals cost tons of mana outside of CH and Torpor - anytime you can take advantage of levelling without taking damage you'll level the fastest.