Since there are so many English speakers out there, and I assume many of you are English readers as well, I just wanted to post some useful info. Especially if you live in the Kansai area. There's a new English bookstore in Shinsaibashi, Osaka, called Random Walk. It just opened on the 11th, and has the most foreign books in Western Japan. It's owned by the same people that own Aoyama Book Center, and they've got a really good collection. If you're looking for 洋書、check it out!
Ah, that's good to know. We live in the U.S., but my wife is from Osaka so whenever we go to Japan we usually stay in the Kansai area. We should check that place out the next time we go there.
Also something to keep in mind is that amazon.com in Japan sells english books as well, at the american price. I haven't tested it fully, but they look to have the complete selection available.