I know I might get flamed for this one, and it's just a matter of opinion - but as far as modern digisub quality goes, I don't mind AMV's with downloaded footage. The difference in quality with DVD is minimal, if the compression is done right, and I'd much, much rather watch a well-made digisub AMV than a badly-edited DVD rip AMV.
If you ask me, this is not a real technical issue (for most), but an ethical one. For the fansub ethics discussion, go see this thread. All that needs to be said was said there.
http://www.animemusicvideos.org/phpBB/v ... hp?t=17615
Then again, this is coming from a guy who can't tell a 192 MP3 from a 320 one... perhaps because I'm too busy appreciating the music itself...

The Birds are using humanity in order to throw something terrifying at this green pig. And then what happens to us all later, that’s simply not important to them…