My thoughts:
Nintendo will probably keep the Wii U name.
$300 will probably happen
It will NOT launch in November
It will compete with current tech, obviously
It will support multiple tablets, they just won't be required.
Don't think the Wii U tablet will be an iPad, just a large DS touchscreen.
Yep there will be scanning toys a la Skylanders
MMOs will not come to the system because "Nintendo is teh kiddie"
Gamecube VC games is a must!
Will not have a strong line-up, probably a Mario game and a sports mini-game compilation (& Steel Diver 2

)
The 3DS is already planning on having retail games for download, so it's a given that the Wii U will do so as well.