Maryland:
-Rams Head Live- Baltimore, MD - Large club, capacity around 2000 I think, barricade, easy to get to, good parking, safe area, good sound, decent sized floor, multiple bars, a few balconies. Awesome venue, but it only gets bigger shows (PPND, AP Tour, All Time Low, etc.)
http://www.ramsheadlive.com/
-Ottobar- Baltimore, MD- Smaller club, capacity around 500, no barricade but stage dives are not allowed. Kind of a sketchy area. Gets smaller shows (TWY, You Me At Six, A Lot Like Birds are among upcoming shows)
http://theottobar.com/
-Recher Theatre- Towson, MD- Mid-size venue, capacity around 1000, in the suburbs. Gets mid-sized shows (The Early November, Thrice, Less Than Jake)
http://rechertheatre.com/
-Sonar- Baltimore, MD- Mid-size venue, capacity around 1000, never been, but I've heard it's very hot and gets cramped.
http://sonarbaltimore.com/
-Mt. Airy Fire Hall- Mt. Airy, MD- Small venue, capacity around 200, no stage, booked by a small booking company who gets smaller shows (Fireworks, Handguns, With The Punches, Man Overboard) and a lot of local punk/metal shows. Nice small venue, easy parking, in the suburbs. I only wish they got more good pop punk shows.
http://www.facebook.com/apexbookingshows
-Charm City Art Space- Baltimore, MD- Never been, but I know there's no stage, and they're a DIY venue that gets small punk/hardcore shows (Handguns, La Dispute, Title Fight, Crucial Dudes). In downtown Baltimore, no idea about parking, location, etc.
http://www.ccspace.org/
-Merriweather Post Pavilion- Columbia, MD- Mid-sized amphitheatre, capacity around 15,000. Warped Tour comes here, along with many other large summer tours. In the suburbs, good parking, really nice venue for Warped.
http://www.merriweathermusic.com/
-The Fillmore- Silver Spring, MD- Large club, brand new, in Silver Spring which is near DC. Gets large acts (Mos Def, Flogging Molly, Widespread Panic). I know nothing about parking/quality of the venue, it just opened recently.
http://fillmoresilverspring.com/index