When I started this thread, I pointed out there are two aspects of copyright, the first being actual copyright, i.e. the right to make copies of a book. The second is derivative works. They really are two very different things, that IMPO should have different protections. I'm fine with longer actual copyright periods (i.e. the right to copy a book) as long as the book remains available to the public, or some mechanism to make sure that an author gets a fair royalty on the book, much like the music industry has.
I would favor a much shorter period for derivative works, especially as the link to the original work becomes weaker and weaker. Making a LOTR movie has a much stronger link to LOTR than writing a book set in the LOTR universe, having an orc or hobbit in you D&D based adventure book is an even weaker link.
I ran across a somewhat interesting paper on fair use
http://jessicadickinsongoodman.com/p...yright-policy/
It's basically a senior thesis, but it's interesting in that it lays out many of the arguments we use, plus it has a very nice footnotes and bibliography as well as gives a pretty good history of copyright and some of the efforts to extend copyright.
The romantic view of authors mentioned in the thesis is the basis for extended copyright and the idea of copyright as property. The quote from Jefferson's letter about why what we know call intellectual property (he doesn't use the term) is not the same as property is of particular note.