One of my favorite distention in Tokyo is the are called Akihabara ... It is sometime referred and Akiba. This is a famous electric town where you can buy almost any electronic parts and accessories. If you are in the market for PC, Tablet, Camera and any other gadget, this is the place you need to visit.
Also, Akiba is the birth place of Otaku オタク, Maid Coffee House メイドカフェ and AKB 48.