Mpeg Streamclip FTW
I work in a Tv studio and we use it all the time when we have to rip dvds. This workflow IS NOT optimal because you lose quality with MPEG2.
Also, if the OP is trying to re-cut commercial DVD's (for educational use), you will need to DeCSS it with MacTheRipper. Mpeg streamclip can still convert the VOB's from the hard drive after the rip.