Anydvd: bypasses DVD/Blu-ray protection and runs in the background (not free) - allowing a backup to made successfully.
ImgBurn: creates images of discs to .iso (free).
Virtual CloneDrive: Virtual DVD drive that allows .iso image files to be mounted (as though a disc has been inserted into a drive) and your usual DVD player can be used for viewing (free).
The bonus of the above is the the .iso files can also be burned (for backup, obviously) at a later date. Hard drive prices mean that a lot of storage can be bought for not very much and it's cheaper than always burning discs as a backup.