Smash Bros is a definate sell for me. There was definately poop and/or pee in my trousers when I saw the new trailer. Unfortuantely, I'm out of college and can no longer mosey over to the neighboring stoners' rooms and pick up a match anytime I want to. Hopefully it will be Wifi enabled...
MP3 looks great, Mario looks like a sure sell, Excite Truck looks cool, and Tony Hawk is actually looking pretty fun. I actually have interest in a Sonic game for once, and MonkeyBall looks as fun as ever. Hopefully they can iron out the kinks in Red Steel and get it at a steady framerate and visual quality more on par with the trailer and scans, because as it is it sounds like it plays and looks somewhat rough.
And Wario Ware looks like it's usual awesomely schizophrenic self. Frankly, I can't wait for this system to come out.