Specifically, the Art Museum, and Tokyo City View. Try to get up there for sunset on a clear day - pretty breathtaking views of Mt. Fuji and Tokyo generally and most certainly the best skyline view of Tokyo until SkyTree opens. Don't take any shit they will give you about not being able to take cameras or whatever - go with a coat and put Specifically, the Art Museum, and Tokyo City View. Try to get up there for sunset on a clear day - pretty breathtaking views of Mt. Fuji and Tokyo generally and most certainly the best skyline view of Tokyo until SkyTree opens. Don't take any shit they will give you about not being able to take cameras or whatever - go with a coat and put whatever you want in the pockets, they don't search (but don't expect to go on the rooftop with a rucksack).
A ticket to the art museum includes entry to City view, the top (open air helipad deck) is an extra 300 yen. Obviously get tickets from a Kinken shop.…see moresee less