Here are the current sales for all the games in the poll:
Grand Theft Auto IV (360): 5.4 million
Grand Theft Auto IV (PS3): 3.87 million
Mario Kart Wii: 5.69 million
Super Smash Bros. Brawl: 5.45 million
Wii Fit: 4.77 million
Metal Gear Solid 4: Guns of the Patriots: 1.41 million
It seems that Mario Kart Wii has the most sales so far and the least votes in the poll. xD