I actually found Nintendo's conference to be a bit of a disappointment.
I was disappointed that there was no new Starfox for Wii, and while they didn't mention it at the conference, yes I know about Starfox 64 3D, but I was hoping for something entirely new, like with other major Nintendo franchises. Also, I was disappointed by no live gameplay demos of the 3DS, no tech specs, no release date and no price. Still doesn't lower my interest in the system though.
The Microsoft conference was okay, I really only cared about Gears of War 3, which looks pretty cool. =P Call of Duty Black Ops and the new Need for Speed Hot Pursuit look very cool, as well as Kirby Epic Yarn. The new Medal of Honor also looks promising, but I'm a fan of FPS so that isn't surprising. Another thing that I never watched in the conferences but am reading and watching afterward, is Portal 2!
The first Portal was great and the second looks extremely fun already.
Personally, I think EA had the best conference, I only got to watch Nintendo's, Microsoft's and EA's though. I've read Ubisoft's was a disappointment all around, but I won't judge that because I didn't see it. Ditto for Sony's.