I submitted the 10 quantum pillar/life mark highlander deck. (blame or praise may now commence) I wasn't able to make it (6am tourney, and had plans at 9am) and didn't realize the conflict until after I submitted the deck.
I really like the ideas behind the six mindgate deck and the six flying weapon deck. They're just about the only ones that don't strongly imply what the other six cards are going to be every time. (I tried to do that with my deck, but anyone who used it probably used six cockatrice, or possibly heal or mitosis)
At first glance, the three decks that appear to be the strongest to me are the two monoaether dimshield decks and the fire/darkness deck. (one would be spider or psion fractal, probably psions due to the mirror and the other would probably use six lightnings). With little to no PC possibilities in any of the other decks, these would probably have been very strong. The fire/darkness deck looks like it would be the best counter to those, due to PC for the dims, and the possibility for various CC cards depending on what people were using. (fire bolts or rain of fire most likely)