For me, it's Kid Icarus. The game looked awesome, I love the character in Smash Bros. and the original is a lot of fun (though the lack of precision landing makes it tricky). Also, Sakurai is second only to Myamoto and Gunpei for Nintendo developers. I'm almost as excited for Zelda (the graphics look great despite what IGN says and it looks to be more action oriented without sacrificing the Zelda charm). Of course, seeing as how good Retro is and how well Nintendo 2D platformers usually turn out, DKCR is a must buy as well. My excitement in the past for Nintendo E3's has been low post Wii announcement, but between the game line up and the 3DS, I think I am more hyped than I was in 2006.

DK... i actually cried with the music.

Donkey Kong Country Returns, no doubt!

(Zelda isn't really a new announcement)

Starfox 64 3D.  It is GORGEOUS.

I should have put that in the poll, but made this in between the conference and reading the 3DS game list. :(

My eyes got pretty wet, I couldn't see the game properly ...

:P

Oh wow, I just looked at the screens at Destructoid. It does look awesome. Thank you Ninty!!!

Zelda ... totally unbiased decision :P

Never played  a Donkey Kong game ... think i got into gaming too late for that, but i was really impressed with the trailer.

Can someone tell me the general gameplay themes/mechanics i can expect from this game ?

Also, Pilotwings Resort.  Now we just need F-Zero to complete the trifecta...

DK without a doubt.