In NYC:

Tomoe Sushi

In PHL:

Morimoto

In DCA:

Sushi Ko (iDine restaurant)

For each of these cities, I've been lucky enough to eat at the finer sushi joints in town, and can say without hesitation that the three places listed above are the best options. Some may argue that Masa is better in NYC, and in response I'd say, that if you have $400 to burn on sushi - go to Masa. Tomoe (located on Thompson St. in the Village) is inexpensive and features some of the freshest fish in town. Tuesday nights are especially good - that's when all the fish from Asia arrive...