I'd have to go with Kirby so far. I'm also anticipating Other M and Dead Space 2 pretty heavily, but I already knew about them so they don't really have the same impact. Donkey Kong, Kid Icarus, and Epic Mickey are nothing to sneeze at either.
Zelda should be good as well, but I'm not completely sold on certain aspects of the presentation or the heavy reliance on motion control. I am glad to hear they're trying to make the gameplay experience more dense though. The piecemeal nature of the overworlds was one of my biggest gripes with WW, TP, and PH (didn't even bother with ST), so in that regard Skyward Sword sounds like a definite step in the right direction.