I use a program called Backup Magic. Works great for me. I run it as a Scheduled Task every night and it backs up all the files that I told it to. It will save old versions of files that have been changed it you want it to and the fact that it runs as a scheduled task every night means I don't even have to think about it anymore. I don't use an external drive though. I just copy the data to a second drive in my PC. Once a week, I just copy my "Daily Backup" folder to my external firewire drive.