I'll reply the priest part. I assume you're doing 5mans, right?
First, the spec. I recommend something like http://www.wowhead.com/talent#bchZfurMRzrkfzoh for 5man.
You'll always be in Chakra: Serenity in 5man dungeons. HW: Sanc is basically useless in 5man content. PW:S is a mana drainer, only use it when emergency. Tank healing: put renew on tank, PoM on CD, spam heal with HW: Serenity when u need extra healing. If the tank got below 70% and heal cant get him back, start weaving some greater heals into the rotation. 2 or 3 ppl taking damage: renew and use heal to refresh it. Gheal is they are dipping really low. Binding heal is useful too when yourself also taking damage. 4+ ppl taking damage, CoH on CD, PoH if the damage is more than 20000.