Well, I voted "anything that beats me" out of principle
I play a lot, exclusively the arena since it was released, and I must say that even though they're not necessarily the most annoying ones to me, the number of fire stalls, speedbows and immo decks that I vs is just plain boring.
I sometimes feel like there are only three decks out there, you play 10 immo rushes, 15 fire stalls, and then you just want to puke because the next one you play has yet another quantum pillar with an entropy mark...
But well, that's just the way things are, and even though it's sometimes annoying, I don't think much can be done about it.
Oraclebows, creamtion deck and firestalls all get my vote because of their originality.
Totally agree with that.