my usual kill order is: right, mid, left. reason: right and left are not tauntable, mid is. right (big guy) pins, he must go down first. as soon as mid goes down, i can then taunt left.
a funny thing happened the other day though, our healer died early in the fight, while we were about halfway into right mob (big guy), so it was just tank (me), and dps. we killed right, mid, left without a healer lol. we were alive, but barely.