One of the best things to help you keep sane while living in Japan is staying in contact with family and friends back home. If you are like Kana and I then that means having a decent computer, a web cam, a digital camera and a highspeed internet connection.
If you are looking to buy a computer or build one yourself there are plenty of options in Osaka. You need look no further than Den
Den Town (aka Nipponbashi) , however you can order anything you need online as well and have it delivered to your house the next day.
For parts, I buy at Tsukumo (http://shop.tsukumo.co.jp/) which is located down in Nipponbashi a short 5 minute walk from Namba (Nankai/Subway) Station. Back in 2005 I was able to buy everything (case, motherboard, cpu, ram, hardrive etc) to build a fairly smokin AMD Athlon 64 3500MHZ for about $1700.00 CDN, but I could have easily built one for $1000.00, I just wanted a real fast PC. I generaly found that price savings when compared to buying in Canada were to be found in the high end items. Prices on mid-range items were quite similar. Used item prices are substantially less than comparable items in Canada.
For used computers I went to Sofmap (http://www.sofmap.com/), they were more expensive than Tsukumo for parts, but had way more used computers and laptops. In 2005 I picked up a Dell P4 2.2ghz Desktop for about $350.00 CDN which was a pretty sweet deal. They also had tons of laptops if that is your thing. Sofmap is located just down the street from Tsukumo.
There are tons of computer shops all over Nipponbashi, but those are two of the big names that I have personally shopped at. For more information you can visit the Den Den Town website (in Japanese Only).
There’s a Two Top (http://www.twotop.co.jp/) Computer Store close to Kana’s folks place so if I need an extra hard drive, DVD-Burner or web cam it is very convenient to check there first. Two Top carries a little bit of everything so they may not have what you are looking for but it is a good place to start.
For more general technology items (DVD players, TVs, Cameras etc) and computer peripherals (printers, keyboards, mice) you will do well to check Yamada Denki aka Techland (http://www.yamada-denki.jp/). It would be comparable to Futureshop in Canada and Best Buy in the United States. Prices are pretty good and the selection is not bad either.