Pat's Hubba Hubba on Main Street in Port Chester, a Westchester tradition, is my choice. It's the greasiest of geasy spoons and great. Their chili cheese fries are the best. I believe that they're open late into the night and only closed on Sundays.
The chili is very spicy if I recall correctly isn't it cookiez? Only went once but had them and they were good. It is even greasier than a greasy spoon though - if that's possible. And no bathrooms - probably a good thing come to think of it.