JW
Gateway
Keybridge

MAYBE the Pentagon City Residence Inn too

All are at or close to Metro stops.

SKIP Crystal City....the 3 times i have tried to check in there i have been treated rudely by desk associates and managers....who REFUSED to comprehend that the EEO B1G1 certificates printed off the website were, in fact CERTIFICATES and not ads. Three or 4 different people....they refused to call customer service...needless to say, i walked across the street WITHOUT a ressie, and they took care of me!

The Gateway will let you eat in the dining room when the lounge is closed-pretty yummy...they let you get the full buffet!

I would not stay out by Dulles (but I have, since the rates are usually cheaper!!) BUT, you will waste a lot of time getting in to and out of DC!