DVD43 is a free application that runs in the background and decrypts DVDs on-the-fly.
Supported OS: Windows 7 (32 bit), Vista (32 bit), Windows XP, and Windows 2000.
WinX DVD Ripper is a free dvd ripper that can encode to mp4, mpeg, wmv, flv and other OS specific formats. The free version does not remove DRM however but if you use this with DVD43 it is pretty functional and fast.
HandBrake is an open-source, GPL-licensed, multiplatform, multithreaded video transcoder, available for MacOS X, Linux and Windows.
Handbrake is a good DVD ripper, current version will rip to mp4 and mkv, older versions will rip to avi also. When used in combination with DVD43 it is useful for ripping DVDs with DRM(digital rights management)
Great for converting videos for iPad etc…