I got a Wii maybe 6 weeks ago. It's a blast.
I bought Madden when I got it. It's more of an arcade style than the uber-real Xbox/PS3 version, but I like it because you actually point and throw the ball.
A friend lent us Mario Kart, which is awesome. We picked it up right away.
We got Mario and Sonic Winter Olympics. It is a lot of fun. I'm a real pro at curling! We don't have the balance board for some of the events.
I rented Monopoly and Trivial Pursuit for a get together recently. Both are good party games.