The classics, specifically the 6 on NES. (I haven't played 9 and 10 on the the Wii, but they look fantastic!) Even though I know it's one of the less popular classic titles, I think 6 is my favorite. For the longest time, it was the only one my family owned so it was basically the only one I got to play. I think I was in my mid teens when I found and bought copies of MM1, 2, and 3.
Maybe you think LP style videos are ridiculous, but I really enjoyed RhoamMythril's perfect runs of these titles on YouTube. Psychedelic Eyeball also had some race videos that were pretty fun -- I wish I knew a good way to set up that kind of thing with some of my friends/cousins who used to play the MM1-6 titles with me.