How about Bethesda? I got an awesome deep tissue massage from Seth at Ninotch a few days ago. It's about 2 blocks north of the Bethesda metro station.
I also like Mirando Chiropractic for a non-spa type setting. They're in Van Ness.
Also, sign up for Groupon, Living Social, Deals for Deeds, etc. They often have massage deals in the DC area.