Just down the hill from Roppongi lies the upmarket area of Azabu Juban. The area is home to several foreign embassies and its surrounding residences.
Azabu Juban has an interesting shopping strip with a mixture of Japanese and western shops restaurants and bars. Towards the end of August, Azabu-Juban holds one of the biggest international food festivals in Tokyo; a great mixture of Japanese and western foods to try.
Not much interest to tourists visiting Tokyo, but this supermarket is one of the few supermarkets in Tokyo that is open 24 hours a day.
More information: www.azabujuban.or.jp/ (Japanese)