I agree about Dream Wizards. But it is within driving distance of work, so I still hit it once in awhile.
The place in Glen Burnie is ok. They have some old and used stuff, which is nice. When I was playing D&D4e last year, I picked up quite a few minis from them. But then they got kind of quirky about selling singles. One day I'd go there and one dude would sell me a single. I'd go a couple days later and another dude would tell me they didn't sell singles.
Even though it is a bit of a trip, the Game Parlour in Chantilly, Virginia, is worth visiting. They are the closest thing to an old-timey game store I've been able to find.