Great Bar-b-que in DC
If you are going to be anywhere near 14th St., you don't mind crowds, it's nice weather and you like to sit outside, and you don't mind a hip under-35 young professional crowd, I highly recommend the brisket sandwich, beer, and onion rings and/or hushpuppies at the The Standard.
Thiis is not an area known for great bbq.
Hill Country is Texas-style withe the moist brisket being the star of the show. Do not fool around with the pork ribs.
If you want chopped pork, go to Rocklands. They also do sliced pork loin very well, but it is obviously not smoked as long.
Fro ribs, the best place to go is Ray's the Steaks East of the River, in a rather obscure neighborhood with no metro access, or up to Rockville, MD to Urban BBQ. At Ray's they also have tremendous smoked then fried chicken. Outrageously good.
I wouldn't fool around with anything else that's convenient.