Amura is an excellent and authentic sushi spot downtown. It's popular with the lunch crowd; if you go during the lunch rush, go early - like 11:30 - to beat the crowds. It's not as trendily decorated as Ichiban around the corner, and the servers are often harried, but the food is completely worth any wait.
The spicy Bubba roll is a favorite: avocado, cucumber, tempura shrimp, and spicy sauce. The miso soup is wonderful - a great start to a meal.
The lunch boxes are a good deal, too: a range of lunch specials like sesame chicken with rice, served on a tray with tempura zucchini or yam and salad.