It's suppertime, and this thread's making me hungry/nostalgic. In Pittsburgh, Pennsylvania, the Original Hot Dog Shop, also known as the Big O and the Dirty O (it's not dirty, though). Beside the hot dogs, there's a mind boggling variety of variations on the hamburger. And the container for a large order of fries (chips to the Britishly inclined) can be used afterward as the manger in a Christmas pagent, it's that big. Really.< In Kent, Ohio, there's Mike's. It's the one with the Star Wars x-wing fighter out front and the drawbridge around back. the food is good and generous, and the menu is worth the trip in itself.
Also in Kent, but only in the evenings, is Taco Tonto's, in the basement of the Loft Tavern (it's only one story high, go figure). they don't make tacos, but rather burritos as big as my forearm, and done well. Thwere used to be a couple of other good greasy spoons in Kent, but they either shut down or went upscale. Sigh.