bitRipper is free DVD to AVI software that allows you to back-up your DVD's as AVI files on the hard drive. It can be used for one-click ripping as good as for advanced modes. There are all necessary settings available:
bitRipper does not require gigabytes of space to copy all DVD content to the hard drive before converting to AVI. It converts video on-the-fly, copying data and writing it to AVI file at the same time.