Early on I'm loving the U/G ramp deck...tons of ramp and card draw. I also like the Unsummon card that gives you Saporling tokens to stall with. I'm kind of surprised they put Eldrazi in the game.
Also messed around a bit with the Esper artifact deck. Seems a little underpowered without Master of Etheruim but Steel Overseer can get pretty crazy.