The Marlton Diner is also in Marlton - big surprise, I know. It is open 24 hours, but they serve a limited menu late-nights, I think after 11pm. They are a fairly recent diner, and have only been around a few years. I think before that the space was a chain restaurant - Ponderosa? Ground Round? Something like that. As you can see, they spruced it up with shiny, diner-appropriate architecture.

The good thing about the Marlton Diner is that they have very large booths in the smoking section, which is oh so necessary when three of the "Population Five" are smokers. [Yes, Rob, you count!] This means we can all fit into one booth instead of having to split up when we saunter in for a late-night snack.

Familiarity: I guess I've been there more than twenty times.
Rating: It's a nice place to hang out late at night. The waitstaff doesn't crowd you and try to get you to leave. The food is pretty good - I've never gone out of my way to go there, but I'm never sorry I've gone.