Alright, here's my GUESSES. =P
The screen we view the games on wont be on the TV, TV is optional, holograms maybe? Projection? Dunno, something similar. This will allow a fantastic way to play multiplayer because everyone can have their own screen and they can put it wherever they want at whatever size they want. Controller? No idea. I'm still holding on to my "light gun" theory where it controls like a touch screen but you dont have to touch it, just point at it. Logically i've come to the conclusion that that CAN'T be it, but it's the best guess I have. =D
Games? We'll see a SSB trailer first, demos of a racing game (either Wave Race, F-Zero, Mario Kart or something else/new), Super Mairo game, Miyamoto's new game which will be the star launch title that defines the Revolution, Wario Ware Rev, Metroid and maybe (hopefully) Pikmin. Third Party games including a brand new Sega game like Feel the Magic/Project Rub was for the DS, something from Capcom, possibly just RE5 but maybe something else as well or instead. An exclusive Tales game from Namco. A huge mature game from a talented third party developer in collaboration with Nintendo will also be present, all fronts will be covered.
The actual Revolution itself will be a box of internet, no connection necessary, it IS the internet. So it can also be used as a free hotspot for the DS!
Metroid will be the graphical showcase and people will say "wow".