It surely won't keep the title for long but the tallest habitable building in Tokyo is currently the Midtown Tower, part of the Tokyo Midtown complex in Akasaka. We spent a day checking out the sights around Midtown, including the National Art Center and the tranquil Nogi Shrine.
It's best to take Sunshine City's name at face value. And I don't mean that it's filled with sunshine, but that it's truly a city of its own. This enormous complex spreads across four buildings, including the Sunshine 60, which became the tallest building in Asia upon its completion in 1978.