Look into Windows Home Server. Its pretty slick. Can backup complete images of your system, file sharing, remote access, etc. When it backs up files, if you have the same file on multiple systems, it only backs it up once & then creates an index for others.
I actually run servers as my PC's. One is a custom built with 2 Opteron's and the other is a Dell with two 15,000 rpm scsi's and xeon processor. They both are fast. I would recommend either. The key for speed is Ram.
As I said, I use them both as PC's. Don't like slow......:boxing_smiley:
Have you looked at Cabonite? I use it and love it. Much cheaper then a server and if your house is ever to burn down or flood you will still have a back up.