Depends on what format you want them in. Personally I use Any DVD + ImgBurn to create an ISO. From there I use Fairuse Wizard to convert to an Xvid/5.1 AC3 .avi file that is compatible with my other streaming devices such as XBMC and the 360.
There are quite a few out there that are free and useful depending on whether or not you need or want to compress them, many people are now just ripping to ISO or VOB because drive space is so cheap these days. Here are a list of ones I'm using or have used in the past.
For ISO or VOB:
ImgBurn
AnyDvd
DvdShrink + Ripit4me
DvdFab
For encoding the DVD to other formats:
Fairuse Wizard
DvdFab
handbrake
Ripbot - for blu-ray or HD DVD conversions
MakeMKV - still in beta but looks decent