the sim exchange the Wii to sell a million units in Amercia this month

[Zucas]

Halo 3 isn't Halo 2. And most of the time it's hard to sell more units than a previous installment into a series UNLESS, it has some dominating cool new feature that allows it to appeal to more buyers. Such as online in Halo 2 over Halo 1's case.