Riot6, I'm a fan of the Yokohama Sheraton myself, however I only prefer to stay there if my plans call for visiting Yokohama/Kamakura or points south of Tokyo. However if my purpose is visiting Tokyo mainly, then I usually would opt for a hotel in Tokyo itself.

If you are a starwood person, since SPG aquired LeMeridian hotels, there is a LeMeridan across from Shinagawa Station (another stop on the Narita Express, and its also a Tokaido Shinaksen station). Its a SPG cat3 hotel so if you are redeeming points its the same for that hotel and the Yokohama Sheraton. There are also the Prince hotels (its like a whole complex of different prince hotels) in the Shinagawa Station area, that we've talked alot about here on the forums.

I had friends visit and stay at the Crowne Plaza, its not a bad hotel, its a hotel you often get as a priceline result, around 90-100usd if I recall.