Wow, I appreciate the input here, but most of this is over my head. I have over 1000 books in my library. I plan to use the method described here to manage them:
http://manual.calibre-ebook.com/sub_groups.html
So to back up both the books and the tag structure are you all saying I just have to backup the Calibre library in the My documents folder on my computer? The tags and such will just go along with that?
I just plan to periodically put it on an external harddrive.