In DCA, Taste Pilots Grill, they have ribs!! And the BBQ chicken sandwich is so good! Also there is a mexican place on Pacific Wharf...I'm drawing a complete blank on the name but it's good too. Over by a Bug's World behind PT Flea is a little stand, they've got a delicious Cesear salad.
In DL, Rancho del Zocalo is super good, Red Rockets has great pasta, and we always get a Dole Whip!
And we really like White Water Snacks too, they have good stuff, good portions and it's reasonable. It's definitely more like fast food though.....things like sandwiches, salads etc.