Mario Galazy will over take Wario Ware next week, Wii Sports technically shouldn't count because everyone gets in in NA no matter what. Every one buys Wii play for the second remote.
That leaves Mario Party 8 as the only real party game in the top 5 that people buy strictly for that reason.
Expect Smash Bros; Mario Kart, and Wii Fit to bump Wario Ware down the list.
EDIT: On a side note; I don't think you can necessarily call Wii Fit a casual title. Just because the idea of Wii Fit doesn't fit the standard "Sit on you ass, twiidle your thumbs, shoot shit" routine doesn't mean this game isn't hardcore.
I'd like to see one; just one, fat bastard "hardcore" gamer get his ass on that balance board and play the game like it was as easy as Mario Party or Wario Ware.
The people who end up buying and playing this game the way it is meant to be; are going to be dedicated to a daily routine that involves "PLAYING A GAME" by definition that makes them a harcore gamer.
