Shinsen near Shibuya
There is an area "Shinsen" which is close to Shibuya on the Keio train line. This area is well known for housing many Japanese celebrities both television and movie. While it may be difficult to actually meet a Japanese celebrity, unless you know exactly who you are looking for, you can see some of the best estates that are available this close to the downtown area of Shibuya. You might consider this area a sort of Beverly Hills of Tokyo. There is plenty of open space and parks despite the very high land prices. And also one of the campuses for Tokyo University is nearby. A luxurious haven just on the edge of downtown.