Wii Sports gets the top spot because it was such a mega hit upon release. We'll say this about Nintendo, their Wii found a way to connect with the mainstream, in a way neither Sony nor Microsoft could, which is why they're relevant again. This game (included with the Wii) was easily accessible and was the rare game that backed up the claim: fun for ages 6-99. Besides, no other game allowed you to properly conclude a holiday by taking grandma to the woodshed in front of the whole family.
1. Wii Sports