jack, can you be more specific? cheers!
I'm on a Mac, and there are a few good copy/clone apps. Two popular ones are "Super Duper" and the one I use is "Carbon Copy Cloner." In either, you schedule copy routines to run hourly, daily, weekly or monthly, and can copy at the folder or volume level. You can even make fully bootable copies of your complete OS using them.
My personal set up for my images is a RAID-0 array inside my main machine copied to an onsite external RAID-0 array. (AKA RAID-0/1 or RAID-10.) Then I keep a third, simple back-up stored offsite to protect against a physical loss onsite. By using RAID-0 inside my main computer for images, I give up some safety but gain very spiffy image reads and writes, which does save time. Given that array is redundantly backed up onsite, I have my security against a R-0 failure. (Note that with a RAID-0 image array, I have to assume I *will* loose it at some point, and hence the back-up arrays are mandatory.)