Giant is the Kroger of DC, google for one near you.
DC Also has many, many Whole Foods and Trader Joes.
Sushi Taro Dupont Circle - Reservations Recommended
Cantler's Riverside Inn In Annapolis, MD (~30 minutes from DC) If you like crabs, this is the place. Definitely off the beaten path, and worth the drive.
There are several McCormick and Schmick's, good upscale seafood/steak place, google for one.
Jyoti Adams Morgan
Indique Cleveland Park - This place was good, but not as good as Jyoti. The dinner menu is far better the lunch menu.
Pizza Paradiso Dupont Circle
Brickskeller - In Dupont Circle. 1000 different beers, with at least 10 on-tap.
Bourbon - Good solid American food, with an amazing selection of bourbons.
McGinty's Public House - Standard Irish Pub, with good selection of beer on tap. In the Silver Spring mall, close to Walter Reed. Aaron recommends the Reuben.
Lauriol Plaza Dupont Circle, try the Ceviche
Zaytinya Upscale, white tablecloth. Great food, try the fries with yogurt. Close to the Spy Museum.
Pita House Alexandria, VA. Their pita sandwiches are great.
China Town Express, Chinatown - Hole in the wall kind of place, but has great hand-pulled noodles. They have a little window on the street you can watch them make these. Only the four signature dishes are worth getting, they are all $4.95 and a great deal, the handmade noodles (soup or wok-fried), handmade dumplings , or soup buns (rice flour buns filled with soupy broth).
Old Town Thai, Alexandria, VA - If you are in the area, this is a nice place for good pad thai and thai iced tea. Their appetizers are really great. Avoid the seafood though, I found it overcooked.
Vit Goel (Lighthouse Tofu), Annandale, VA - Weird name, but really really great Korean food. The short ribs are amazing. Pretty much everything here is good. Highly recommended.
Mark's Kitchen, Takoma Park, MD - This is just a couple blocks east of Walter Reed. It's an electic restaurant with a sort of granola/eco vibe. Hard to describe the menu here but the food is good. It's like if you went over to eat at your hippy/tie-dye wearing Korean aunt's house. Example: I had the Korean BBQ with side of fried brown rice, pickled bean sprouts and German potato salad (?). Really good though, made me feel healthy.
Meskerem Very good Ethiopian place in Adams Morgan. Does well with large groups (we went there with 7, and they didn't flinch). Definitely tops the Queen of Sheeba.