Talking, here, about the no-frills diners where you can still get your eggs/potatoes/toast with a cup of coffee and a small OJ accompaniment for under $5 and Monte Cristo is NOT on the menu.
My fave (still up and running) is the Broadway Restuarant on Bway 101/102. It's got the feel of a place that's never been renovated, ever. Oddly, the only decoration is numerous pictures of Brad Pitt.
The Metro Diner, a block down on the opposite side of Bway, is not the sort of diner that I'm talking about. A full menu that's useless considering the only thing you want is eggs-and-stuff anyway, and about $3 overpriced.
Where Greenwhich Ave. and W 12th st meet, there used to be the type of diner I'm talking about but it has been replaced by the cleaner, newer one, again about $3 overpriced.