Organize your PDF documents emulating iTunes.
Initially thought to organize Scientific papers actually Papers is so well done that anyone who has to manage a huge amount of documents in PDF format can use it.
The resemblance Papers with iTunes is not so much for its interface but the philosophy behind that is that you can organize your library of PDF documents by creating subfolders, similar to playlists, evaluate them and use metadata valuable and additional information, besides offering comfortable mode screen reading.
Thus, with Papers you will not need to print documents for consultation comfortably. And if you know online libraries, you can easily download your documents directly through Papers. Finally, to find a document, nothing easier: use Spotlight for it.