In the "other"category, I inherited a huge stock of books from a friend who unexpectedly passed away in 1990. Still haven't finished reading them all. I also borrow a lot of books from the local libraries, since my library card will let me borrow from about half a dozen excellent town libraries.
I used to buy a lot of books, but with shelf space and budget limitations, it has to be a pretty important book for me to actually purchase it these days. My main exception is science fiction paperbacks, which I stock up on two or three times a year at science fiction conventions, and usually re-read several times. I also occasionally search through used bookstores for antique books, preferably history books from before 1920.
When I do buy new books, I'm forced to go to a Barnes and Noble down on Route 22. The town I live in and those nearby, although their shopping is otherwise excellent, have not a single bookstore. I'm puzzled as to how this could happen in an area with one of the highest concentrations of advanced degrees in the nation (the former Bell Labs, now Lucent research, is about three miles from my home).