I was last in Tokyo in May 2006. It is an amazing place to visit and with any luck I will be back again before the end of the year.
There is so much to see and to there.
For electronics Akihabara is the prefecture to hit, if you can try to go there on a Saturday that is the big shopping day for the Japanese, they shut down a number of the streets and you have all the vendors out and it is a sight to behold.
The Asakusa Shrine is a very humble place to visit, an amazing example of old Japan. Be sure the cleanse yourself in the smoke before you enter and throw a few coins into the pot and get your fortune. (it is in Japanese and English)
Imperial gardens is amazing it's large if you really want to do some walking.
For nightime fun Roppongi is the place to be. Amazing that at 2:00 in the morning the streets are filled with millions of people. My two favorite clubs are Geronimos and Wall Street. If you are looking for a gentlemens club you can visit One eye Jacks. Just make sure you have lots of room on your credit card.
I could go on and on and on so if you have any specific questions just ask
