The easiest thing to do is to get a couple of external hard drives ( like this one ) and attach them to your machine. Copy the videos over by year. If your main drive fails, you should have no problems with the backup. If you're really worried, once you copy the videos, you can detach the drives and store them in another location. 1tb should cost about $500.

If money is no object, there's a usb/firewire 1tb lacie drive that runs $800