Since the OP stated "South Florida", and since the travelers might come up to broward County to shop, etc, there are some additional recommendations:

Diner: Unlike Big Pink (which I like, but which is more "diner-inspired" than a true diner, Lester's Diner, in central Ft. Lauderdale near the FLL airport, is very much a classic 24-hour American diner in design/decor, menu offerings, and most importantly, in the service by a group no-nonsense but still friendly and hard-working waitresses. If you're there for breakfast or lunch, ask to sit in Georgina's station: she's the best!

Burger: Le Tub, near the Hollywood beachfront (about two miles north of the Westin Diplomat, on the same road as the hotel. A very casual, waterside saloon that also serves food, including burgers that have won national awards. Friendly service:

http://www.theletub.com/


Cuban: I'll second Casa Larios; in addition to the South Miami location, they also have a second location near the intersection of Flagler Drive and the Palmetto Expreessway, which is not too far from the MIA airport. Both food and atmosphere are good at the Flagler location (I have not been to the other location).