Personnally, I'm excepting explosive sales of Wii Fit in Europe. Who know? See the Nintendogs, Brain Training and Eye Training games, they're outselling the japanese versions.
If the USA could be like in Europe, Wii Fit sales will easily surpass the 15 Million but I'm expecting 11-12 millions in its lifetime.
For Animal Crossing Wii, We have to wait, we know nothing and I hope that there will be more fun etc... than the DS version. For this game, the use tyle of the wiimote will be very important for its sales.
Mario Kart DS will be the best selling MK game. I heard MK Wii will only have 32 races. It's the same number than the DS version. Why not add more races?