well i have my pictures on my pc, about once a month i just copy my whole picture folder first onto a 100Gb western digital passport portable usbhard drive which is self powered and quite small, i dont keep this with my computer. then i copy my whole pics folder onto one of my external 500Gb drives. its a twin drive caddy that sits on my disk the whole time. so thats 3 copies altogether
for my old family photos and stuff i would be heartbroken to lose, as well as being on the 3 hard drives, i also have at least 3 copies on dvds which are kept in seperate places around the house, may sound like overkill to have 6 copies but i know id be heartbroken to lose my old family pics, and dvds are so cheap i think its worth it.