Tokyo Tower comes to mind, of course. It's open from 9 am to 11 pm. Great view of Tokyo.

Nearby, the Prince Park Tower hotel has a bar, the Sky Lounge Stellar Garden (I think) has a great view of Tokyo too.

[![View from SkyLounge][1]][1]

[![View from SkyLounge on Tokyo Tower][2]][2]
It even has a view on Tokyo Tower :-)


  [1]: https://i.sstatic.net/O5loM.jpg
  [2]: https://i.sstatic.net/0HFN6.jpg