PDF Library on MAC

It happened by luck...
I was dragging a PDF file, then I dropped it mistakenly on itunes. I expected an error message or something popping into my face. Surprisingly, the PDF file was added ti the library.
At first glance, I thought it would be a bug or sthg :), so I clicked the file, and it opened the MAC viewer to display the PDF file.
WAAW, the itunes support PDF Files :), I am new to MAC world and it is clear that I miss a lot. I decided to give it a chance and check how much itunes can go far with me as a PDF organizer for files on my MAC.
I created a new library and called it "ebook" and I dragged some pdf to that library.
the itunes copy any files dragged to its library. In this case, I will have at least two copies of each files.
from preferences->advanced uncheck the "keep itunes music folder organized" and "copy files to itunes music folder when adding to library".
This doesn't look enough so far, i need some kind of tagging. thx to the "smart playlist" I can automatically assign a keyword and it will be added automatically to this playlist.
Hence, all I have to do is to add a prefix to my PDF files depending on the folder structure i need it to be.
I browse media and documents through only one application now :)
the advantage of itunes was to make a virtual structure. So, it wasn't a big deal where i place physically the file as long as i organize it well by tagging through the playlist, and the file can exist in many playlist (many-to-many relation) and this is sthg u don't get by folders.
Don't forget that this also will work under Windows as well ;)
I was happy with my itunes so far, although it doesn't support search in PDF contents.
searching in PDF contents is supported in Spotlight, so it was not a big deal. Another problem is that files are not opened inside itunes, instead, they were opened by the MAC Viewer.

What else can I have here?
I found a great tool called yep, It is really a great tool. It has the same decent look as any MAC tool.
It does everythg: searching, printing, tagging, browsing..etc it is really a great document store. It is freeware; I hope it remains so.