Hearthpwn

Simply my favourite deck, strong and really fun to play. 

This deck is based on Reno and N'zoth.

Shudderwock: It's main purpose is to bring back N'zoth board and fully heal with Reno battlecry.  The best alternative is Blazing invocation since you could be able to discover a second N' zoth, Reno or Shudderwock itself.

Murmuring elemental: I mainly play it to double Zephrys battlecry,

Zephrys: Can be replaced with Golden scarab that can give a second Hex or other useful cards. Jeweled scarab is good too, since you could gain a second copy of a useful spell such as Lightning storm, Healing rain etc.

Cairne: Piloted sky golem or Piloted Shredder are good alternatives. Piloted shredder could be better due to its tempo value, its rarity and it's more difficult for a priest to deal with it. Sneed's old shredder shoud be fine too, but it's debatable because of the high cost (I tried and didn't work for me). 

Kezan mystic: being a tech card, it can be replaced with whatever card you like depending of which deck you want to counter. I play agaist a lot of freeze/otk mages so I use Kezan mystic to steal Ice block in the exact moment that I have lethal or I think that my opponent is going to make their combo to protect myself (that's the reason why I prefer Kezan mystic over Eater of secrets). Some alternatives: Dirty Rat, Skulking Geist (in this case I suggest to replace Lightning bolt with Zap! or Rockbiter weapon that works fine with Doomhammer too), Eater of secrets, Acid swamp ooze, Gluttonous ooze.

Thalnos: sometimes i just play it to draw, but in case of decks that run really big minions or lots of small one, i keep it to enhance Heartquake or Lightning bolt. Can be replaced with Loot hoarder or Acolyte of pain and since N'zoth doesn't bring Acolyte of pain back, it could be a good choice to avoid fatigue.

Chillmaw: it can be quite tricky to play since there are few dragons in the deck, so that you have to be sure to have dragons in your hand when you need to clear and to be sure not to have them in your hand when you bring Chillmaw back with N'zoth. I actually had no problems with it, but if you think that it's too difficoult to handle, it can be replaced with Primordial drake, Khartut defender or Hagatha (but keep in mind that you could significantly weaken the board summoned by Shudderwock).

Mechanical Yeti: Can give you Time rewinder to return Shudderwock to your hand. 

Devolve: A good altrnative can be Plague of murlocs. 

Healing alternatives: some alternatives to Healing rain and Jinju Waterspeaker are: Hallazeal that you can combo with Hearthquake or Walking fountain.

In some of my alternative versions of this deck, i run Elise Trailblazer too to generate some additional value and avoid fatigue longer, Archivist Elysiana or Elise Starseeker, to turn spells or minions that might not be useful in the late game (such as minions that draw cards or bordclears) into something that could serve a better purpose. Kel'thuzad works fine too.

Remember that weapons are included mainly to clean the board, but they can serve other purposes too, due to their versatility. Even if you deal several damage to yourself killing minions to gain/keep board control, you can fully heal thanks to the healing capability of this deck; in some cases tho (mostly vs otk and combo decks), weapons might be an awesome means to put pressure on your opponent by costantly dealing direct damage.

I decided to run the Charged hammer because it helps to control the board in the early to mid game while keeping your minions alive. In the late game the new hero power can help keep the board under control or push for lethal in some cases. It's great when your board or hero are frozen and you want to put pressure on your opponent before they can reach their win condition. 

You have another great advantage here: Chillmaw. Most of players I encountered, had no idea on how to play around it and played minions before killing it; as result, they lost more minions for no reason (es:paladins that hero power first, mages that play Mana Wyrm first etc). Moreover even if they do know how to play around it, it still deals 3 damage which is a good Aoe. Chillmaw can be dangerous for your board if you still have dragons in hand when you play N'zoth, so tbe careful.

Ancestral spirit is another card that some people can't play around. When I use it on a taunt, they kill the taunt and then try to go face, so you can use it at your advantage.  

Sorry if my English is poor, I'm not a native speaker and I'm still learningXD

If you need more informations or tips, feel free to ask :)