Tastiest thing I've ever had has to be the homemade pizza my relatives in Michigan made while we were there. Didn't think I'd ever eat pizza with a fork but nevertheless, it was amazing. Basically a rich mix of pepperoni, hamburger and sausage, and it just had a homemade taste, not like anything from a franchise.
However, I won't be going back up there for a year at least... so current favorite food has to be a Runza sandwich. Midwestern food chain, pretty decent. Close behind that is a homemade pasty - both are basically hamburger, potato (maybe not in a runza) and various spices and whatnot in a bread shell .. only the runza is soft and a pasty is a larger sort of crust. Some Runzas have cheese.. but that's just gross
