Takeshita Dori - a pedestrianized street (between the hours of 11am and 6pm) in Harajuku Tokyo that is filled with restaurants, cafes, fashion and accessory stores and a lot of people. Most of the stores are aimed at the younger generation so you will see a load of students after school hours too.
When I first came to Japan, I would come here to buy whats known as Nama Shashin 生写真] ( unofficial or paparazzi photos ) of my favorite idol at the time - Nishida Hikaru. Today, they still sell Nama Shashin here of the most popular idols like AKB48, Arashi, and more.
If you are looking for some casual clothes and want to see the latest trends with young folks then this is where you should come. Get off at Harajuku station on the JR line. Close by is Meiji Jingu park which you can also enjoy. Harajuku is also home to one of the largest toy stores in Tokyo - Kiddy Land.