As I said in the "Wii3" thread...
I Predict that This event will be a dissappointment to anyone expecting more than just launch info and general hype. If there's any secrets left, I doubt they're of much interest.
The invitation implies that Nintendo is inviting many people from outside the usual confines of the industry. I doubt they'd spend much time revealing new games to those that are unfamiliar with the console in the first place.
A lot of stuff we already guessed will be confirmed and launch details will be ironed out.
That being said, I can't believe Zelda is finally on the horizon and I can't wait to hear about the new control scheme.