As I write this, my sons are playing on the refurbished Nintendo Wii they got for Christmas. It's an old enough console that it's probably verging on "vintage", but the great thing about getting an old system is that you can pack your library with only the best games ever made.
I usually rely on the IGN Editor's Choice list to figure out what was the best of the best.
We're currently rocking Skyward Sword (Zelda), Super Smash Bros. Brawl, and New Super Mario Bros.
Also, Angry Birds Star Wars, just because Dean digs it.