Hearthpwn

This deck's goal is to disrupt the opponent early on with mana wraiths and northshire clerics and draw out their precious removal. Eventually, it will capitalize on several bigger creatures to take over the game and win.

Early on the mana wraiths and northshire clerics will waste your opponent's hero power and delay many early plays. The mana wraith especially works really well in this deck as the priest has several tools to keep the creature advantage to the priest. Between healing, cheap removal, shieldbearers and the power word: shield they will have a difficult time sticking a creature to the field.

The best part of a mana wraith however is that your opponent will have to spend mana first to remove him as a threat. Meaning that the you, the priest, will be the first to drop creatures on curve again.

The lategame of this deck exists out of several beefy creatures that just have good stats and very relevant abilities. Most of them will have at least 5 toughness, and their abilities will help out keeping the control. Some stand-outs are the auchenai priests. Many decks can't handle 2 damage per turn to any target so it's a priority target. It's fine on turn 4-5, and great on 6 and up because you can do the damage right away. The one demolisher acts as the third copy of auchenai priest. It's also an amazing card to stick early and buff with a shield/bearer.

The deck also has some hate for rush decks out there. The cabal shadow priest murders rush decks like it is nobody's business. Your early game already gives you more than a fighting chance, but resolving this guy will be the final nail in the coffin for a rush deck. The holy novas are also against rush decks, but they're generally good value. The temple enforcers are a nightmare for mage decks and any damage-dependent removal.

A stranger choice might be crazed alchemist. I've found that he really does a lot of work for the priest. It can pull a 4/x creature into the range of the priest's removal. You'll thank me when this allows my chillwind yeti to deal with one of those 4/9 dragons.

Everyone who ever played a priest has noticed that there's often not much to do on turn 2. Our hero power does nothing right out of the gate. This deck has statistically nine times out of ten a relevant spell on turn 2, and a pro-active turn one or two play three out of four times.

There are still some things that could change to this deck. I'm not very impressed with the chillwind yeti in this deck, and think it could be changed to a violet teacher without much issue. Similarly, the earthen ring farseer could be better as a shattered sun cleric or big game hunter. I'm trying to find a spot for a mass dispell and a second blademaster. Also, depending on where you are on the ladder, I might maindeck a mind control for a legendary. Speaking of legendaries, I think Cairne Bloodhoof would do well in this deck because of the estimated value he will have. Finally, Eventually I might consider changing one of the shadow word:death to a holy fire because it hedges on killing x/5's, of which there are many. On the other hand, the 3 mana versus 6 mana could make it too slow for the deck.

Edit: I've changed several cards in the deck. The basic lay-out is still the same. The main changes are the inclusion of two holy fires, an azure drake instead of the archmage for mana efficiency and that the drawn card often ends up mattering. I've made two versions of the deck. One of them has Mogu'shan wardens because I really needed another big taunt to protect the fragile creatures like the demolisher, and the warden is a great deterrent against any rush strategy. The other version plays a thoughtsteal and a violet teacher instead. I think these two cards have merit in the deck, even if the violet teacher isn't at its best here. I think the thoughtsteal is  too slow against any deck relying on rushing, but great against control decks. I'm still undecided if I should cut another card for 2x mogu'shan wardens AND a thoughtsteal.