Nathan,
a great shop is very much a subjective thing. The Reef Tank has limited stock but very reasonable prices and good people. They are the most hobbyst friendly store in the area, by far.
The Marine Scene in Herndon has real good stuff, but also limited stock and very high prices.
The Vienna Aquarium, in Vienna of all places, has good fish selection, low corals but very high prices.
Roozen's, in Fort Washington has an incredible selection of both fish and corals and resonable prices. However be warned, it is a 'production shop'. They mix fish that should not be together, do not have correct lighting for corals, and have a high death rate. But they have almost anything you can thing of. If you can get past the 'oh my God, I can't believe they put that there' feeling, it is an excellent place to stock your tank.
The Aquarium Center is Randallstown is another large shop. Outstanding fresh fish selection, average salt fish, just ok corals. Prices are slightly above average. However, they have an excellent dry good selection.
I have never been to Exotic Aquatics in Baltimore, but I hear they have good things and correspondingly high prices.
Glenn is correct, go to
www.wamas.org and find out when the next meetings are. I am sure you can get plenty of frags from the various members.
Eddi