[Sangetsu]

If you are going to Tokyo and plan to stay at a hotel, I recommend you try the Prince Hotel in Shinagawa. The hotel is next to Shinagawa Station on the Yamanote line, which means you can access the most popular parts of Tokyo conveniently (the Yamanote line encircles the heart of Tokyo). The last time I checked, the room rate was about 8000 yen per night, which is an excellent deal for a modern, private room in metro Tokyo.

On the Yamanote line you can make stops at Shibuya (to see Hachiko and Shibuya crossing), Harajuku (cosplayers, clothes shops, etc.), Ikebukuro (the Ikefukuro owl statue, I have no other idea why people like Ikebukuro), Ueno (home to the Ueno zoo, Tokyo National Museum, the Museum of Western Art, and the duck boats), Akihabara (electric town, where you'll find electronic items which cost more than they do in America, but which you can't use without an electrical adapter), Tokyo (where you can walk to Ginza, the Tsukiji fish market, or the Imperial Palace), Shinjuku (where you can visit Kabukicho, or the ni-chome neighborhood, which your username hints you might be interested in).

In Ginza you can take the Ginza line to Asakusa (traditional Japanese souvenir capital of Tokyo) and visit the Sensoji temple. The Edo/Tokyo museum is located fairly close to Asakusa, as are Tokyo's most famous Sumo stable.