Hearthpwn

I hope you have fun with this deck - I DID :) It is not cheap and it takes some time to learn how to pilot this beauty, but it's definitely worth it. You can create lots of CRAZY COMBOS. You can suprise your opponents and beat Big Priests, Even Shamans, Odd Warriors, Jade Druids, Even Warlocks and generally almost every other T1/T2 decks. Odd Paladin and Mechathun Warlock seem to be the worst matchups.

If you want to hit fast legend, this list is probably not for you, but if you seek for a competitive deck and want to have fun at the same time, you've just found it ;)

HAVE FUN!

 EDIT:

I replaced Counterfeit Coin and one Necrium Vial with 2x Tar Creeper as deck was lacking 3-drops, and needed something to stop aggro in the early game. Creepers also work well with Barnes, Kobold or even Sonya, cause they give you 3/1 taunt instead of 1/1. It can also protect your Umbra or Sonya from being removed too easily.

EDIT #2

I replaced Cairne Bloodhoof and 1 copy of Sap with two copies of Infested Tauren to stop early aggro, as aggro decks are the biggest problem for this deck. It's also additional protection for your Umbra, Sonya and Thuzad.

EDIT #3

Infested Tauren didn't work as well as I assumed and It's 4-drop which I have a few on my list so I replaced it with 2 copies od Mistress of Mixtures. They fit nicely, as I was lacking 1-drops and they counter aggro decks much better then Taurens. I replaced Kel'Thuzad (which was too slow and didn't generate much value) with Baron Rivendare to generate more crazy combos :) Last but not least, I repalced Sap which usually seemed unecessary with evergreen Emperor Thaurissan . It's a great target for Kobold Illusionist or Barnes. It enables you even more crazy combos (Sylvana+Cube, Umbra+Sneed, Whelp+Zilliax and more).