I live in MN. I can't really say I have a favorite coaster, some of my favorites would be Wild Thing, Renegade, SBRBP, Avatar Airbender. Although Valleyscare probrably tops all of them.
Former Minnesotan here...Renegade is pretty easily my favorite ride there, though I'll always have a soft spot for Corkscrew since I worked on it for a summer.
I live up in the Anoka area, My favorite ride would probably be renegade or wild thing. But the best ride that, "isn't a coaster", Would be the Power Tower.