Sushi restaurants north of Boston???
Sushi Island is the best in the area no question, but if you don't want to go quite so far:
Sushi Corner in Melrose is reliable, consistent, and reasonably priced. Great for takeout!
All Season's Table in Malden is a fun, swankier place to try. Their sushi is good, very nicely presented, and they also have a good range of other styles of asian cuisine if you want to mix it up. I really like to order a selection of apps to build a sort of asian tapas meal there along with some sushi. Their menu is online: http://www.allseasonstablerestaurant....