One of the smartest, most thoughtful discussions I’ve seen about ripping backups of DVDs you own, from MacWorld Staff:
Is DVD ripping illegal?
The MPAA and most media companies argue that you can’t legally copy or convert commercial DVDs for any reason. We (and others) think that, if you own a DVD, you should be able to override its copy protection to make a backup copy or to convert its content for viewing on other devices. Currently, the law isn’t entirely clear one way or the other—Fair Use proponents claim you have the right to make a back-up copy of the media you own whereas those who support the Digital Millennium Copyright Act say that the DMCA overrides Fair Use.
Go read the rest here.