Returned again to the Tokyo Hilton in December and was not disappointed. I find this hotel to be a convenient hop from the airport on the Airport Express even though it is a bus vs a private car. It is also a short walk underground to the subway just off Shinjuku so getting around is fairly straight forward and the concierge will help with instructions, tickets and directions.
The hotel is usually quite busy so book early, I find it quite full but reasonably quiet for all the business they have. The exec lounge is a good place to work and catch up on things while traveling. On a clear day you can see the mountains and get a great sunset from there.