I haven't counted in recent years, but my guess is that I have about 5,000+ books, as a very conservative estimate. Might be alot more, but I've not been down to the basement storage closet in a while.
When I bought a new house a few years ago, I designated one room on the main floor the library because it had a wall of built-in bookcases. I put 4 more large bookcases into that room as well as a lovely leather loveseat, and for 'end tables' I covered two 3-stacks of paper boxes (snagged from work) with small table cloths...so 6 more boxes there. And that is only one room. In the living room, I have two more large bookcases and two smaller bookcases, at the top of the stairs, another bookcase, and upstairs in my guest bedroom, I have a full set of plastic sliding drawer boxes under the bed (3 drawers on each side) full of books (mostly novels). Finally, I have about 8 - 10 boxes of books in a large storage closet under one of my sets of stairs....and about 50 more books in the master bedroom on night stands, a shelf, on either side of the dresser mirror, etc.
Most of my books are non-fiction, the following being the largest topics:
History - particularly Russian history, the French Revolution, and American involvement in Vietnam...but really, all kinds of history.
Travel - world travel is my passion, and I have lots of travel books - narratives, old guidebooks, coffee table books - you name it. Also, my old Russian books and other language guides.
Theology and related - mostly Catholic and Jewish thought, moral theology, doctrine, church history, etc, but some Protestant-related books as well. Also a nice little library on Buddhism.
Mount Everest - I own about every book ever published in English about mountaineers and mountaineering on Everest. A few books about other 8,000m peaks like K2, for example....but mainly Everest.
Classic film - I own a ton of books about the development of the film industry, the histories of all the major studios, the development of the various genres of film, biographies of directors and actors, etc. Some of these books, in particular, are rare 1st edition collectors items. I have one book related to Rudolph Valentino (published just after his death in 1926) that is worth well over $1,000, and several other books that range in the high hundreds.
Causes - I have a reasonable collection of books related to causes I have been involved with over the years.
TV shows - I have a nice little collection of non-fiction books related to my favorite TV shows - companion books for everything from all the Trek shows to Buffy/Angel to LOST to Roswell to Dark Shadows. Also, all the Babylon 5 season companion books and the entire script collection.
I have other books, of course, about all kinds of subjects from gardening to art to cooking (bread baking mainly, but others too) to dogs to classical music...but those are my largest non-fiction collections.
About 1/4 of my collection is fiction - and is made up primarily of classic literature (particularly Russian literature), detective novels (Sue Grafton, Jonathan Kellerman, etc) and spy novels (David Morrell, Daniel Silva, etc). I'm not that much into scifi books though - I actually own the entire DS9 relaunch...but have never gotten through a single book.
