My personal belief is that the Wii is America's newest, cheap toy that everybody must have. I also believe that the software will catch up with the Wii's success and the sales will stall. Right now, the Wii has very little in the way of "innovative" gaming to make the concept a truly successful one. Once consumers understand this, they'll move on to another toy. That's not to say that the Wii will forever remain a toy, just that right now it's nothing special.
Sometimes it hurts to go number 2.