The Baltimore area has a bunch of diners, a lot of them are the neon-filled, all-night or open late kind which I hear is similar to New Jersey and New York. A lot are owned by Greeks or Italians. The show Diners Drive Ins and Dives has been to the Baltimore area many times.
Boulevard Diner - This is a diner in Baltimore County, Maryland that the show with Guy Fieri has been to. I used to frequent this place all the time and it has a small town atmosphere as does the surrounding region despite being a suburb.
Now I live in West Virginia and there are a lot of country-style diners. They do not have the neon and chrome look of Baltimore diners but they often have a lot of homestyle decorations and have a very intimate feel, with a lot of "country" elements and décor. now these diners often close early, like around 7 or 8 PM, meaning they close earlier than many chain restaurants and fast food places.
Topspot Country Cookin' - This is officially a "restaurant" but many locals call it a diner. This is the only sit-down restaurant in my town other than a Chinese place. Everything else is fast food or you have to drive 10 miles to the city. People also consider Waffle House, which other parts of West Virginia have, a diner. This place has served President Bush twice and has some great homestyle, fresh cooking.
Though I haven't seen it there is a movie called "Diner" that is supposed to really represent the Baltimore of the past when things were nicer in the city center before everyone who could move to suburbia did. "Waitress" is a movie that is set in an unnamed town in an unnamed state but could very well have taken place in West Virginia. In both Maryland and West Virginia I've seen the occasional old pharmacy that still has the old lunch counter inside which is real neat, mostly in the small towns.