The deck I was most scared of was the blue/white control deck running supreme verdicts etc.
Luckily I didn't end up playing against one, and since it was the beginning of the gatecrash format most of the decks played were some sort of Aggro/Tempo Deck.
Round 1:
Played an interesting mirror match type thing against Bant Midrange with Thragtusks and Trostani's and the like, I went over the top with Armada Wurms although he had some interesting tech with Stolen Identity and managed to copy my Armada Wurm twice (netting himself four 5/5s, I managed to swing for exact next turn due to Gavony Township making my wurms bigger than his)
Round 2:
Played against Mono-White Humans
I ramped too quickly for him to deal with and got much more value and size, allowing me to just go over the top and beat him into the ground
Round 3:
A Midrange/Aggro Werewolf deck with Mayors, Huntmasters and Hellriders. Yet again my ramp was too fast and got a turn 3 Sigarda in one game, and a turn 4 Armada Wurm in another, and the following turn I Resto-Angel'd the Wurm,
Round 4:
Boros Aggro, Trostani turns off aggro decks. If they can't deal with her the value generated was just too much for them to beat down. I hit massive life totals and just didn't need to block. It wasn't really a race, when you gain 10 life off an armada wurm and 5 more the next turn when you populate for the token.
Round 5:
A weird brew using pack-rats and other tokens along collective blessings to get huge. I thought I kept a good opening hand with 3 lands and 4 dudes, but then I didn't draw any more lands. Game two I curved out perfectly and won, in the last game I misplayed hard, throwing away my dudes in un-profitable combat trades and basically lost myself the game because I wasn't thinking.