(Ronald Reagan) Washington National Airport DCA is much smaller than LHR, having only 17.8 milion passengers per year. However I think it is well equiped with shops and eating places.
http://mwaa.com/_/File/_/shopnational.pdf
The shops range from Victoria's Secrets, Brooks Bros clothes, to a Smithsonian Museum shop, a National Geographic shop, a real (small) bookstore, on down to tourist schlock, 36 shops in total. I do a lot of my Christmas shopping there because there aren't crowds and the selection is pretty wide. There are 35 places to eat. Eleven are before security including Legal Seafood, a sushi place, TGIF, etc. The other 24 are fast food places or bars on the 4 terminal fingers near the gates. One can get food and then sit in the glass-walled terminal wings and eat it.
Dulles (27 million pax last year) is not quite so convenientlyl equiped with service since most places are scattered in the various midfield terminals near the gates.
http://mwaa.com/_/File/_/shopdulles.pdf
BWI (approx 22 million pax/year) has 32 eating places, about half of them in Southwest's big new area which includes a real seafood restaurant, Phillips. There are about 22 shops, again about half are in Southwest's area.
http://www.bwiairport.com/customer_a..._terminal_map/