Priest

Healing and Spell Power, Spirit, then Intellect.

Penance and Prayer of Mending are cheap and frequent; Spirit keeps you casting.

Healing and Spell Power, then Spirit and mana per five.

Big heals cost big mana. Regen is the long-fight stat.

Spell Power, then Spell Hit, then Spell Crit.

Devouring Plague and your other DoTs can crit now, so crit is worth more than it was.