Tokyo City View Observation Deck may be the sleekest of the city's many observation centers. You can find it on the 52nd floor of the Mori Tower, which is the centerpiece of the new and modern Roppongi Hills building complex.
The Sky Gallery is a 360 degree panoramic observation room split into three separate sections. Gallery 1 offers a view of Tokyo Tower and Odaiba, Gallery Two showcases Yokohama and Mount Fuji and Gallery 3 overlooks Sibuya and Shinjuku. The cost of admission allows you to enter all three. For an extra fee it's possible to visit the Sky Deck, an even higher open air rooftop observation center.
Also included in the price of admission is entry to the adjacent modern art museum which spotlights a rotating series of exhibitions. If you have more money to spend there is a planetarium show as well as several bars and restaurants.