Flying Elves. Who'da Thunk It?
I can't help but start with an elf build, just because beatdown is always so much fun. This is a throwback to the fish design of old. Evasion combined with bounce is a staple, and this set has added some excellent cards for that design.
I think that this deck, on the surface, appears to be a total beast and might be something to watch out for. Other cards for consideration are Fact or Fiction, more countermagic, and the possibility of Aether Mutation. I think that this is the build you want to start from and modify based on what decks you feel are going to be most popular. You'll see this design again in G/W/U and something very similar in G/U/B.
You can also replace the Sentinel and Champion with other creatures to not go with an 'elf deck' but I actually believe that this is the best configuration for this set of colors. You have extreme tempo, mana-fixing built into the cards. If Memory Lapse had been printed I would definitely include it in this deck.
Without a third color (such as W, B, or R) you can't make an effective control deck with these two colors. The cards in this format don't support it. I'm looking forward to those decks though, because I think that there are many new designs waiting to be explored.
The next installment is going to look at the much hyped (and rightly so) B/W deck. Its going to be one of the premier decks of the format.