In the past we have examined OggConvert and Thoggen, two GUI tools for simple encoding or transcoding video into free Ogg formats. But if you are interested in codecs other than Theora and Dirac, you have a lot more options to choose from. Let's consider two utilities that advertise both ease-of-use and quality: RippedWire targets DVD ripping and conversion specifically, and WinFF, which can convert DVD content and other video sources.
Both apps are ports to Linux from other operating systems. RippedWire is derived from HandBrake, which originated on BeOS and has gained a substantial following on Mac OS X. WinFF is a front-end to the FFmpeg library, and as its name suggests was originally written for Windows.