DVD copy for personal use?

I want to burn a copy of a DVD for personal backup that's scratched up while the players can still read it. I haven't followed the legalities lately but I hear that it's illegal? Last I heard there was some kind of funky thing where it was illegal to sell the program with the copyright un-blocker so they would offer a free "upgrade" on the website? Not sure these days what's going on, I just don't want to have to pay for another copy of The Wall.