I use Nero 6 Ultra - allows you to burn CDs and DVDs, and
recode double layer DVD movies so that it fits on a
standard one-layer DVD+R or -R.
I hear there is a little copy protection-breaking program
called 'AnyDVD' that can run in the background to allow
you to duplicate the data on most DVD-Videos if that's
what you want to do. I don't know much about it, though.