I certainly haven't tried enough sushi places in SF to say it's the best, but one of my hubby's and my favorites is Fuku Sushi in the Japan Town Center (towards the Fillmore end). Small/intimate and always very good quality. I've read some of the reviews and it sounds like the service isn't great if you sit at the tables. We always sit at the sushi bar, so we haven't encountered that problem. Their hamachi kama is a.w.e.s.o.m.e.!!!

I'd be interested in hearing what folks think is the best best sushi in the city, too!

Umi in Potrero Hill, not trendy, not huge but always the best quality for fish and preparation. The fish is either flown in direct from Japan or is all local sustained or enviromentally sound fish. Really good place for sashami and nigiri, the rolls are good and they do a few small plates of seared or grilled fish. They don't do other kinds of japanese cooking so it's all about the sushi. price are reasonable although it adds up quick especially with the daily specials. The have a different menu for each day depending on what was fresh and best that day. They also a good sake list without be snobby or expecting you to buy lots of bottles. The hosts are the co-owner and the chef is also a co-owner.