I highly recommend Sushi Cafe on Wells in Chicago. There are a million sushi joints to go to, but I love this place. The sushi is cheap, always fresh, and the service is very friendly. I love their dragon roll, and anything with barbecued eel.
Sushi rules... Deep Sush in San Francisco (29th and Church in Noe Valley, to be exact) is the best I've ever had. EVER.
I love sushi. My favorite sushi chef just retired about six months ago and it hasn't been the same since.