I would look at the dual format DVD burners. That way, then you can choose the format that you want to burn, and buy one of the less expensive ones, and find out later what is compatible with your DVD player.
You can't just directly burn from a movie DVD, because like you said, dual-layer, and I haven't seen a DVD burner that we can buy that is dual layer. So, what happens is, the movie DVD's are 9.4 GB, compared to the 4.7 GB that we can burn at home.
I thought that x copy got shut down, so you'll end up having to pick up a couple of free programs, DVD decrypter and DVD shrink, that will do what you need. This link is a link to an article done on the Screensavers, and this is what I do at home to back up my DVD's.
ps. I forgot to say that this will rip the movie to your hard drive, so you'll end up needing about 10 GB free on your hard drive.