In DC we like to get our sushi fix at Sushiko. Sushiko is always fresh and flavorful, and their roll combinations are just right. Some of our favorites are the Tuna and Jalapeno Ura-maki roll, or Shrimp and Cilantro Ura-maki roll. The Dragon Ura-maki roll with barbecue eel is really good, if you are into that kind of thing. And of course, there is the California roll. I recommend upping the ante and getting the genuine blue crab (only $1 extra) as opposed to the crab stick.
The original location is in Glover Park, but due to popular demand, they have opened up a second location in Friendship Heights. While the ambiance does greatly differ (the original really isn't much to write home about), the food itself is superbly consistent. Be it either location - Sushiko is highly recommended.
Added Bonus: They deliver! within the immediate surrounding area.
If you haven't dived into sushi-loving just yet, I highly recommend giving it a try, but start by getting your feet wet slowly, as I did. Begin with the vegetable rolls (ignore any eye rolls from the already established sushi eating snobs, you'll get there), then slowly introduce some of the raw fish rolls. Begin with more familiars, like a Shrimp roll or Tuna roll. Then branch out into a delicious Eel or Rainbow roll. Finally, once you are comfortable with the rolls, you can learn to appreciate the genuine non-roll sushi with fish atop rice. My favorite is the Scallop nigiri.
Nigiri - Raw fish sliced thin and served on top of a small mound of rice. No seaweed. Usually comes in pieces of two.
Maki - Rolled sushi. Generally a vegetable, a fish, or a combination, wrapped in seaweed and rolled in rice. Sometimes the seaweed is inside the rice (Ura-Maki), sometimes the seaweed is outside the rice (Hosa-Maki).
Hand Roll - A cone-like shape usually made of seaweed, or some kind of fried cornucopia, filled with raw seafood.
Sashimi - No rice, no seaweed, just the raw fish or vegetable. Known to some as real sushi.
Tempura - Fried goodness.
Admittedly, it took me some time and development to learn to appreciate sushi, but once you get there, you will never go back. It's tasty, delicious, and oh so right (even healthy, too!).