A great, free utility which I came across recently is DropBox.com. It is an offsite, online, secure backup and synchronization facility, but that makes it sound far too complicated. In fact it is a folder on your desktop which you can access from anywhere and from any machine. You can access the files from a web browser or install the software on multiple machines and have copies of your files held on each machine and all kept up-to-date all the time. For indexing, you can keep your current work files in the DropBox and know that you have a secure copy in case of machine problems. But it also makes transferring files between machines easy. So if you have a scanner attached to one machine in the house and want to work on the scans from your laptop, scan the images into the DropBox and they are there on the laptop too. You can also allow other people to share your files, controlling which files they can access
What really makes DropBox different is its simplicity. It installs quickly and easily, is easy to understand, and simply works. 2Gb of storage is free and you can pay if you want more.
I would probably not choose DropBox as my main backup solution, but as an extra line of protection on your current working files and a way of moving files between machines it is very useful.