I have so many favorites, I don't know which I like more.
In no necessary order.
Super Mario Bros. - Main Theme
http://www.youtube.com/watch?v=MEKDF_WbMlg
Super Mario World - Overworld
http://www.youtube.com/watch?v=EJn5HM3b9bI
Mario Kart 64 - Rainbow Road
http://www.youtube.com/watch?v=fpyJ-P3pSFQ
Sonic The Hedgehog 2 - Emerald Hill Zone (2-Player)
http://www.youtube.com/watch?v=dnilJPn0Dm4
Yoshi's Island - Athletic
http://www.youtube.com/watch?v=mxRxWY7qK3w
Super Mario Galaxy - Tension
http://www.youtube.com/watch?v=ZFarjrvza4c
Mario Kart Wii - DS Delfino Square
http://www.youtube.com/watch?v=Xgd6sagGudU
Super Mario Galaxy - Good Egg Galaxy
http://www.youtube.com/watch?v=x8hJz8xFyHw
Mario Kart Wii - Rainbow Road
http://www.youtube.com/watch?v=TTsdonXl6dE
I think that's enough links for now.
