Clam chowder is particularly great from a diner, for some reason. The one where I worked as a student did lovely Manhattan clam chowder - the first day it was made it was kind of bland, but the next day, when it had reduced a bit, it was lovely. And if you were lucky enough that there was any three-day-old chowder left, and you could rustle up a bit of garlic bread to go with it...heaven.