Hearthpwn

Just made this list for climbing the ladder, having been a long-time Priest player. Currently floating around Diamond 4, hoping to take it or another version to Legend this season.

The deck thrives off of the spell synergy of Sethekk Veilweaver and Renew, although it has a couple of other packages included that keep it from getting bulldozed by the Aggro-heavy meta. Of course, the Quest gives you some lategame potential, but this list doesn't have the legs for a protracted lategame battle as some of the Resurrect and Galakrond lists do. You want to play the tempo, board control game and keep your opponent from stabilizing too much.

Cards like Imprisoned Homunculus, Reliquary of Souls, and Overconfident Orc should make up your early minion package, although sometimes on an empty board you can sneak in a Dragonmaw Overseer to amazing effect. If you can buff your taunt minions on a small to empty boardstate, both aggro and control decks have a really hard time dealing with you.

Getting quest active can be your plan against control and midrange matchups, although landing good Psychopomps and Shadow Madess woll do you a lot better in the early to midgame.

You want to keep the board clean and maintain minion control, setting up for powerful board swings with Sethekk Verilweaver and Exotic Mountseller. With quest active your small minions become a lot better lategame.

Card Choices:

Double Holy Smite and Shadow Madness: These combo very nicely against most decks with Sethekk Veilweaver and Exotic Mountseller, especially against pesky deathrattles (i.e. Zixor, Apex Predator).

Dragonmaw Overseer: Played this card incidentally a lot with my Galakrond Priest (through hero power) builds and found it to be consistently good. It needs to be dealt with right away if you play it early with your good cheap minions, or you can combine it with a good taunt minion (Overconfident Orc, Convincing Infiltrator, etc.) for a big board swing. Also combos quite nicely with Psychopomp as it turns that terrible 3/1 body into something useful. Reanimating this card with reborn will make your opponents tilt.

Exotic Mountseller: Another way to turn your cheap spells into something useful mid/lategame, combos terrifically with Sethekk Veilweaver. Another threat that needs to be dealt with right away or will go out of control, on a nice body to boot.

Edit: Removed 2x Imprisoned Homunculus for Injured Tol'vir and Apotheosis. Homunculus was a trial basis card and has bad synergy with Psychopomp.