I can't speak to quality or reputations, but I know there are flight schools at Manassas (HEF) and Leesburg (JYO) in Virginia. I'm not familiar with the Maryland side, but would think Frederick (FDK) would be one possibility.
If you're closer to the Baltimore side of DC than the Dulles side, I'm not sure what to tell you. Hopefully others will have more input.
Another suggestion is to go to
Airnav and pull up airports near you. They'll have a list of FBOs and flight schools on the field, with phone numbers and web site links.
If you're an AOPA member, give them a call. That's their backyard, and they might have some suggestions. Just a thought.
Sorry I can't be of more help. No matter where you go, make a list of questions you want answered ... type and cost of aircraft, availability of instructors, experience, quality of maintenance, etc. Call around to several places and write down their answers to these and other questions, then compare and make the best choice possible.
Good luck!
R
