I don't know why, but I appear to be in the minority when I say I recommend Elantris. I think it's greatly underrated- not the best written of his books (though still very very well-written), but man it blows your mind. I know you're waiting for the new edition, though, so I'll have to stand by.
Mistborn. I'll say Mistborn.
I'd like to reiterate something I saw somewhere. I'm probably going to say it wrong, but here's what I kept thinking of during my Elantris reread:
"Other authors carefully drop occasional clues throughout their books so as to heighten the shock of the twist at the end. Brandon Sanderson throws hints like a drunk clown throwing confetti, and you're still blown away at the end."