EWR - Term C: The Garden State Diner (round about Gate 82) there's also a Nathans (similar area) and an A&W stand (but that's over by the 130 ish gates) all good heart attack on a plate fare - yum
LGW - South: I think it's the Metro upstairs over in the left hand corner (looking west) reasonable croissant, coffee type of thing and excellent view over apron and rwy.