I have successfully backed up and restored both windows and linux machines with partimage: http://www.partimage.org/. Some features:

• It compresses (gzip or bzip2) the allocated parts of filesystems, and leaves out the unallocated.
• It can work in client server mode over the network.
• It can automatically split files, e.g., on the 2G boundary
• Available on live bootable linux cd:s such as knoppix