I dont group by type, but in no particular order:
Good all-around menu, can be pricey if you like apps but they're all VERY WORTH IT. phenomenal wine menu.
Grill from Ipanema.
Brazilian. They can do amazing things with meat. Fantastic rum drinks too.
sustainably caught seafood.
the chef is amazing. wide selection of fish and you wont feel guilty about it. the salads are dee-lish as well.
more casual than the above but always tasty, always fun. pretty standard tex/mex/cuban menu that has whatever you want. tasty drinks and good service. plus it's close enough I can walk to it.
Uni -- A sushi place
good sushi restaurant that isn't too crowded for dupont circle. they have this one roll that's hit with a blowtorch and is SUPER tasty.
tasty greek food. cheap and quick... can't go wrong.
Delicious lebanese / mediterranean in georgetown. served up "tapas" style so you can share with everyone.
Pizza Paradiso (G-town)
decent pizza and a beer list to die for. beer it up and wash it down with a slice.
Kramerbooks (Afterwords Cafe)
yeah, I know, it's a book store but the food is awesome.
OK that's a good start. go eat.
just off the top of my head.