Shopping is an integral part of your travels in Japan. If it isn't in your itinerary, it should be. Harajuku is fantastic for an extreme wardrobe makeover, Okachimachi is one giant flea market that stimulates all five senses, and Akihabara is a well-known electronics heaven. The Japanese economy relies heavily on consumers. Despite the rather stagnant economy recently, you do not need to mindlessly follow the horde of Japanese consumers just for the sake of it. Shopping in Japan can also be as cultural of an experience as is ringing the bell in a Shinto shrine.
Calling itself the "Creative Life Store," Tokyu Hands is a department store chain that houses multiple floors of stationery, gifts, cooking utilities, home decorations, furniture, gadgets, and super kawaii toys. Wandering around the huge complex, you will quickly realize that apart from providing hours of pleasure and making you miss the last train back to the hotel, Tokyu Hands gives you an insightful glimpse into popular Japanese culture and Japanese ingenuity. Many of the goods make great gifts to take home, and aren't expensive. Take a look at their brochure too.
Tokyu Hands has multiple branches all over Japan, while their biggest one is in the Ikebukuro district in Tokyo and is well worth the visit. Other locations include Shibuya, Shinjuku, Ginza, and cities such as Osaka, Kobe, Hiroshima, and even Sapporo up in the north. Thanks to the invention of the Internet, you can do some online browsing of the Tokyu Hands merchandise without traveling all the way to Japan. The website is in Japanese, but you are sure to find unusual, bemusing goods leaving you puzzled for a while. They also offer worldwide shipping through the "Tenso" service.