As far as shops go, I think this thread is pretty current:http://www.styleforum.net/showthread.php?t=165226
If you decide to shop around the Aoyama area, you can stop by Meiji Jingu shrine, the entrance of which is at the top of Omotesando. Other popular tourist stops are Asakusa and the Tsukiji fish market. Taking in a baseball game or (on odd months of the year) a sumo tournament may also be fun, depending on your interests.
Sukiyabashi Jiro is eye wateringly good sushi, although you'll pay at least $200-$300 a head to eat there. The yakitori restaurant Gonpachi in Nishi-Azabu is popular with tourists and you should be able to get away with English there. You might also have fun just checking out some of the more local neighborhoods just outside the central wards, like Shimokitazawa or Kichijoji (both on the Inokashira line which departs from Shibuya). There you'll find good food, cool bars and interesting people.