One personal note from a different viewpoint. If I only had 50 books I wouldn't be using software at all, I'd be dragging the books over to the phone with Windows Explorer. Software becomes valuable when a computerized solution is able to manage something that's become unwieldy or downright impossible to do manually due to complexity or scale or some other factor.
In CC's case, when someone hits a few hundred books, that's when you hit the knee of the value curve and CC comes into its own. At that point there's no longer any way to keep a book inventory on the phone, updated and accurately grouped by author and series, without a software solution.