Actually Ghost supports
incremental backups. so you dont have to do the complete backup every month.
I use ghost, and Make an image of the "c:" drive on my external usb drive. I save it in a folder named "c 2_2_2007" telling me it was last backed up on 2/2/2007. Ghosting to a hard drive, if you dont clutter up the c drive with a bunch of crap only takes about 15-20 minutes. I keep about 15 gigs on the c drive, and everything else on the external.
I also keep an
extra external, and copy the first one to it incase it crashes. you cant be too safe.