Hearthpwn

Had surprisingly good results with this deck, about 85% win rate through rank 9. It should be pretty self-explanatory, but anyway; hit your opponent as often as possible, instead of his minions. Use Power Overwhelming and Soulfire for finishers. Power Overwhelming (and some other cards to lesser extent) also combos with Void Terror - great against some decks, a bit risky against others. I used to run only one, but they turned out better than I expected. If you want to replace cards from the deck for some reason, like maybe adding some legendaries (I have no good ones myself), these are the card choices I'm the least sure of:

Imp Master (Kinda slow, but great against decks without much aoe, plus Knife Juggler's best buddy)
Succubus (Recently added, not tested enough, but 4/3 seems very good against a lot of decks)
Shattered Sun (Really shines when there's a lot of creature trading, but that doesn't happen very often. Also decent for buffing good creatures to survive some aoe)
Void Terror (A bit gimmicky really, but surprisingly good. Two might be too many though)
Young Priestess (It should be good in theory, but literally always gets killed before it does anything useful)