The DMCA explicitly requires the Library of Congress to "make the determination" for fair-use exemptions. The DMCA says "No person shall circumvent a technological measure that effectively controls access to a work protected under this title." The Library of Congress's exemptions do not include copying for personal use; in fact, proposals as simple as requesting access to circumvention of CSS for operating systems where "legal" decrypting is not available have been dismissed three times.

That said, this is about bypassing encryption. If you perform a bit-for-bit rip of the DVD and play it back with licensed software, you should be okay. But I bet most people are using mplayer or VLC, which are not licensed.