DVDShrink is free and the standard for easy ripping of DVDs.

DVDDecrypter is also free can handle some of the newer copy protection schemes, but is a little more opaque to use.

RipIt4Me is a free program that integrates DVDShrink and DVDDecrypter and provides a Wizard-based interface for easy ripping.

AnyDVD, as previously mentioned, is very effective but on the expensive side and it most run in the background.

DVD Fab HD offers a free trial (and, I think, reverts to the basic program after trial expirate) and does an excellent job at ripping. It was able to handle DVDs that DVDShrink and DVDDecrypter could not.

StarBurn is another good program that offers a free trial (and, I think, remains free at the end of the trial period -- I may be wrong, however).

DVD ripping is not hard, but involves a little bit more than audio CD ripping, particularly when you come up across a bizarre copy protection scheme.

Hope this helps.