I just watched Nintendo's conference while chatting in the gamerDNA channel. If E3 was a contest, Microsoft already won... unless Sony brings it. I think it's less than an hour for their show, so I'll be there.
The thing that most appealed to me is the new Metroid, but to be honest I didn't play any of the earlier games yet, so I'm not terribly excited. :S What about a new Zelda game? I would've liked to see that! The new Mario stuff looks nice... familiar, but/so nice.
As for the rest... it seems I'm really not Nintendo's target audience. They really should show more games (and I mean actual games), and talk a lot less, but that goes for all conferences.