I'm in DC for work 4-5 times a year, and if the trips are Thu/Fri I always try to stay until Sunday and stay at a different property on Friday and Saturday nights. I'm a big fan of HR Dulles on a Friday night - comfortable rooms, good breakfast, free parking, short drive over to Reston Town Center. And sometimes it's cheaper to fly out Saturday at noon than trying to fly out on Friday night.
Looking at this weekend coming up, almost every Hyatt property in the metro DC area has a rate of < $107 for Friday night. HR Crystal City is higher (probably a conference) and obviously PH is higher.