Looking very much like a gigantic Pez dispenser, the Bunkyo Civic Center Building, just north of Tokyo Dome City, is one of a handful of Tokyo skyscrapers offering a free observation deck. The 25th-floor deck boasts a 330-degree panoramic view of Tokyo, centered on north, that includes the skyscrapers of Shinjuku and Ikebukuro as well as the new Tokyo Sky Tree tower. On a clear day you can even see Mount Fuji.
The view is best at dusk and nighttime, but note the early (8:30pm) closing hour. At the south end of the floor is a casual restaurant looking out over Otemachi, Ginza and the Imperial Palace.