Why not dedicate the room to your own library, complete with comfy chair and reading lamp?
Let's address the stacks. It sounds like you need book shelves and lots of them. This may sound obvious to some, but countless times I've seen people struggling with how to get five bookshelves-worth of books into two bookshelves. Line the walls floor-to-ceiling with shelves, if need be.
The organization of a book collection should support browsing and the ability to access a specific volume quickly - which is how public libraries are organized. Libraries typically organize fiction by the author's last name and non-fiction by categories. You may want to do the same. Categorize the non-fiction books by topics that makes sense to you. Imposing the Dewey Decimal System or the Library of Congress Classification System on a home library is a little like shooting a fly with an elephant gun. Not to mention your classification may differ from the library classification systems. For example, the Dewey Decimal System classifies some of my organizing books as "home economics," others as "psychology," and some as "business." In my mind, they are all "organizing books."
Do you still have a lot of books within the sub-categories? Alphabetize non-fiction by author or title within the sub-categories. Only organize to the point where it's helpful in locating specific books and browsing, but no further. Dedicate a shelf or a few to each category. Labeling each shelf with a category name will make it easier find a specific book or an area to browse.
With your books physically arranged on shelves, half of your organizing project is complete. The important project of cataloging your collection is yet to be done. The benefits of cataloging are
- having an inventory that is suitable for the insurance purposes (think about how much money have your spent on your collection),
- reducing or eliminating duplicate purchases,
- and making informed decisions regarding the management of the collection.
If you don't mind a little manual entry, the website Library Thing (www.librarything.com) provides a unique combination of cataloging with a virtual bookclub. Enter the book's author, the title or the ISBN and the website fetches comprehensive information about the book from different websites which is then used to populate your inventory. The website offers social networking with other site members so you can chat about your latest read or get recommendations for the next. Joining Library Thing is free but there is a $10 /year fee - or $25/ life - to catalog over 100 books. It's an amazing amount of functionality for the cost.
Books are well-loved by many, including myself. Loving something is a reason to keep it, but treat it like you love it. Give it a place of honor and take care of it. You can have more space and energy for the things that are important to you by letting go of the things that you no longer love and no longer serve you.
One post script: the sites www.collectorz.com and www.readerware.com also have cataloging software for other collectibles such as music and dvds.