If you want to stay in Maryland, try to keep it west of conn. ave. places like Bethesda, Chevy chase, Kensington or Rockville will be safe and offer easy access to the safer side of the red line of the metro. If in dc it gets a little more spotty, but as a very general rule west of 16 th st nw will be good, and west of rock creek park is good no matter what. As for close in va. The advice above about Alexandria and Arlington is spot on, both are nice. While there are some nice places in prince George's county md, they are few and far between and surrounded by bad areas. That combined with not a lot to do there would make me stay away from there as well as southeastern Montgomery county (silver spring etc.). I'm assuming dc attractions will be the focus of your trip, and if that's the case I would avoid staying too far out or you will spend far too much of your time just getting into town and finding parking. That said you would be missing out huge by not taking a day trip or two to places like the northern va wineries and Annapolis.
