Moody's Diner, Waldoboro, Maine.
This place should be declared a national treasure. I don't think I've ever spent more than 20 bucks for two people, and most of the time it's far less. The food (Maine style cuisine) is all from scratch, always good. They've got stuff like pot roast, meatloaf, turkey dinner (real turkey, cut kinda sloppy off the bone.) THE BEST pies, chocolate cake with peanut butter frosting, homemade whoopies as big as your dang head. The waitresses call you deah (the Northern equivalent of hon.) Moody's has been open since the 1930's, I think. If you're ever in Maine, that's the place to go, though maybe not during tourist season, as it gets packed with loud people.
edited to add- Oh yeah, and they'll even make you up a plate of veggies and a biscuit if you don't eat meat!