I've set up a page with links to all the fun otaku stores that I've teamed up with (and frequent whenever possible). There's CD Japan, J-List, RightStuf and of course, the online powerhouse, Amazon. You can reach the page by clicking on "Otaku Shopping" on the main menu or clicking here. Mitte onegaishimasu! I've picked a good mix of books, study aids, figures, messenger bags, plushies, anime and more. Of course, once you're in, you can browse and shop from any department within the store.
It's a win-win situation: you get your otaku fix, while contributing to my Get Out of Debt and Play More Fund. Happy shopping!