Splint, if you're not already doing so, you have to try Fab's AutoBackup 4. You can set it and forget it. It's awesome. You can run Fab's, nuke and pave(reformat) and reinstall all the customers info. When you hand it back to the customer, they'll wonder if you did anything at all,

because it will look exactly as they gave it to you, wallpaper, icons, browser settings, user accounts...etc. I HIGHLY recommend it. All you need is one big drive for the data to transfer to and from. No disposable media needed, unless the customer requests it. Check it out, it's worth every penny.
Fab's AutoBackup 4 LinkEdit-it also works on a failing drive or an infected drive if you use a Linux live CD.