The wii version (road trip) will be the best seller among the 3 consoles, if only because its the best thing to use the balance board since wii fit. The sheer saturation of balance boards on the market should drive high sales for such a title, shouldn't it?
I've heard more than one casual observer refer to Wii Fit as a console, and because Wii Fit and the balance board out consistantly out sells the PS3 and x360 (individually), i think it will have a noticeable influence on software, despite the majority of its buyers being "casual."
To be more direct: Road trip will have impressive legs, and be a million seller by late next summer (ironically so because its a snowboarding sim).
Thoughts?