I had lived in in DC for five years when my parents came to visit a year and a half ago and tapped into their immigrants-from-Taiwan-in-the-'60s network and discovered three Chinese places that were better than the places I'd been going to.
1) Chopstix, on Jefferson or Washington St in Rockville. A terrible name, in a strip mall, with no decor or atmosphere to speak of, except that it reminds me of places in Los Angeles that I go with my relatives and eat myself into nirvana. The food is not quite that good, but there are lots of non-typical dishes decently done. Also, you get a great pork-and-seaweed soup with your meal. It may not be to everyone's taste, but I can vouch that it is like at least one person's mom' cooking.
2) A seafood place whose name I cannot remember, nor the name of the street. It is in a strip mall BEHIND one of the strip malls on the west side of Rockville Pike. It is in the same strip as Wild Bird Food, and the name of the strip is Congressional or Federal or some such.
3) Tony Lin's, on Rockville Pike. Not GREAT, but better than the average Chinese around here.