My favorite mario games were Super Mario Sunshine and Super Mario World 2. I guess that the Mario Party games were good, but there were like 8 of them, so it got repetitive. I think Sunshine was the best, though, because of the unique style of play. Plus, the fruit-eating Yoshi eggs were cool.
Mario Kart has to be the best. I used to like the Mario Party games, but they just get so repetitive. I used to have a Game Boy Mario game that I really liked, but I forget what it was called.