A few things mentioned above - Spam and milkshakes. As for scrapple, it's available in most NJ diners south of I-78. I get my fill of it, since I'm a serious diner fan.

Fried seafood of any kind, except squid, which I don't consider to be food. Pecan Pie. Onion Rings - battered, not breaded. A few Chinese dishes - Walnut chicken or shrimp. Sweet and sour chicken. Fried wantons.
Mexican food - real Mexican food from a real Mexican restaurant - three enchiladas - one beef, one bean, one cheese with a huge helping of refried beans.
Sicilian style pizza. Reeses peanut butter cups. peanut butter and bacon sandwiches.