Here is a neat trick. You can use Itunes, a free and fairly stable program available in both windows and OSX versions to organize and categorize your PDF collection. The program can auto-copy into a storage directory and allows you to group the files in various ways.
http://lifehacker.com/software/pdf/g...nes-240447.php
Sadly, it will not work on DOC or RTF or LRF or other file types. Has anyone found a program that allows the storage and cataloging of these various files types?