I have an external Western Digital hard drive always plugged into my computer. I backup the entire "c" drive every night using the Retrospect program that came with the drive. I take digital photographs daily and oftentimes improve them. I would hate to lose any of my work. I also use that external hard drive to "drag and drop" files I only access upon occasion. I also have done a Ghost back-up to dvd's. But I am not going to spend that time very often. So the external hard drive always attached gives me one layer of hope that if I lose the data on my computer it will be available on the external hard drive.
I also have a second external hard drive. When I have time I copy the entire My Documents file there (including any pictures) and move that away from the computer. I never want to lose year's worth of data and pictures.
All of this is not very time consuming once it is setup.