If you want to seem really fucking cool take your friends to back bar in somerville. It is an absolute bitch to actually find, you'll probably need to ask someone where it is.
I have no idea if I've written about these places.
Oishii is easily the best sushi I have had in Boston. I have now had every specialty maki and sushi on their menu and can tell you they are all worth it, though some of them aren't the most imaginative things in the world. "The" Maki and the Kobe beef and pear maki are my two favorite rolls with the foie gras with truffle being my favorite specialty sushi. I personally haven't had any of the entrees from the kitchen, however I have had a few of the cooked appetizers (usually specials that night) and liked what I had. That being said from what others have told me the cooked entrees don't seem to match up price for quality.