Kinda far out from DC, but I'd have to recomend the LBS here in Laytonsville, MD. JRABS Bicycle Shop. Not a big operation, their online store prices are very competitive. I can order things and not pay shipping if I PU in the store. I service my own bikes so can't comment on their service, but others who do get their bikes serviced are complimentary about their work. The owner is very knowledgeable about obscure parts and bits to keep my older bikes rolling.