You might want to take a look at Tellico at
http://www.periapsis.org/tellico.
It's a KDE application (sorry, no winders) for "collections" but exports bibliographic data with ease -- does searches and imports at Amazon, Library of Congress, and other sources, works quite nicely and, well, it's free. I'm using it for my library and for research materials and it's handling over 2,000 titles efficiently.