I don't know as much about these guys as most of you, but I'd have to go with "Koopa the Quick" from Super Mario 64. I'm pretty competitive, love to run, and know how to find a shortcut if I need one (on the road). I'm pretty sure this guy took one in the first level of Super Mario 64 since he disappeared from view and then winds up coming up another hill.
Also, the princess Daisy in Mario Kart Double Dash reminds me a lot of one of my friends based on her hyperactivity and expressions.