Just a heads up for a solid, cheap lunch option on 7th between 20th and 21st. I've been to Tono six or seven times in the past few months, and have found it to be one of the best "cheap sushi" values in the city, or at least in the nabe.
They have various cheaper specials, but I generally opt for a $9.95 deal that includes two rolls, two pieces of sushi, and soup or salad (beverages extra). Very few of their rolls are off limits for this price - had a very good softshell crab roll yesterday, for example, without a problem. I've found their tempura rolls to be quite good - tempura is still hot and crispy within the roll. Rice was a bit too warm on our last visit, but that's the first time I've found that to be the case.
The fish seems fresh - my spidey-sense hasn't tingled once yet, and I generally tend to be the guy more acutely aware of this than others I eat with. I've found the salmon in particular to always be fresh, with good texture.
It's a bare-bones operation - you order at the front of the restaurant, and go back up to collect it from them when it's ready - but everything I've tried at Tono was solid, and you can't beat the price.