As far as I am concerned the best in Baltimore was (and probably still is) Soundscape on Cold Spring Lane (just a hoot 'n a holler from my
alma mater).
http://www.soundscapemd.com/ Soundscape descended from an old, old Baltimore hifi store called Park Radio downtown. Spent lots of quality time there when I was an UG. Bought Polk speakers, a Philips tt, and a Yamaha amp from them in 1978 and still have and use them all. Great folks (John Dorsey, his brothers, and others) there who sold good stuff, let the sound do most of the talking, and skipped all the pretension.
Gramophone is also still around in (near) B-more and was good, as well. Bought a pair of Dynaco A-25s (used) there for my parents in the early 1980s.
There was another place on Hartford Rd near the city line that sold excellent stuff but had a pretty snooty staff - I won't mention the place's name

-- but AFAIK it's also long gone.
The funkiest store in Baltimore was a little shop on 25th St called (IIRC) Custom Music. Full of fantastic vintage gear in the 1970s - wish I knew then what I know now; I'd have bought one of those Marantz 8Bs they had! I did buy my first good tt there, used, ca. 1976 - a Philips GA-308. It served me, and later my parents, well or decades.
There was another funky place downtown - EDIT: I believe it was called High Fidelity Centre - that sold a unique mixture of junk and wonderful stuff. The proprietor was a guy I'd met on the CB radio

He introduced me to the Transcriptor Skeletal turntable, Grado cartridges, and the Shahinian Obelisk speakers. Note that JA Michell (a descendant of Transcriptors), Grado & Shahinian are still alive and well -- heck, Shahinian still makes the Obelisks, AFAIK.
Myer-EMCO in the DC metro area is, sadly, no longer with us.
I did occasionally venture into - and even, less occasionally, buy stuff, from the local Stereo Discounters storefronts around the city (more often at their big annual hifi "show and sale" at the Timonium fairgrounds) -- but I am not necessarily proud of that
There was another chain in the Baltimore area which later became (or merged with?) Bryn Mawr and ultimately got sucked up into Tweeter. I am blanking on the name. I remember listening to big Infinity speakers there and covering my ears in defense of the shrillness thereof (playing a Mannheim Steamroller LP, no less)!
Another interesting but short-lived stereo store in the B-more area was opened by Gordon Miller Music in the late 1970s. They also sold records - good selection and very good prices, as I recall. I only remember buying records from them (which is probably part of the reason they didn't last too long).