I keep all of my books organized in Librarian Pro by Koingo Software. Admittedly, the Windows port is a sort-of-slow version of the Mac software, but it’s usable and rather pretty.
Along with this, I use a USB barcode scanner to import items by their EAN/UPC barcodes. Librarian Pro connects to Amazon’s APIs and loads book metadata based on that barcode.
After importing a book, I make sure to tag it with a code of my own, specific to my collection. For that, I have these stickers:
And voila, an electronically-catalogued library of books awaits. It’s pretty easy to add location information to the metadata to help look for books, as well as generate HTML pages to show off or sell used books.