Hearthpwn

This is a very good deck. I tried it multiple times before posting and I won 5 times in a row. The purpose of the deck is killing enemy's Feugen and Stalagg quickly, with Big Game Hunter, Shadow Word: Death, the spider that spawns from Nerubian Egg, Auchenai Soulpriest + Circle of Healing, and then taking control of the board.

Why are Feugen and Stalagg in this deck?

Simple, their deathrattles refers to your opponent's Feugen and Stalagg too. So you just need to make one of yours die to summon Thaddius, that is pretty insane in this fight. 

Video: https://www.youtube.com/watch?v=PhPR3ZZUPAk

Notes:

If you prefer you can replace the ogre with Sylvanas Windrunner, Ragnaros the Firelord, Cairne Bloodhoof.

Also, Cabal Shadow Priest is not mandatory. You can replace it with a second ogre, Azure Drake or the cards listed above.

Mind Control Tech is useful to steal a minion either when Haunted Creeper(s) die, or if Thaddius manages to put 4 minions on the board in the first 4-5 turns. Btw most of the time it will just sleep in your hand :) So I REALLY SUGGEST that you sub it with a second Big Game Hunter (I have only one)