"A family of four will certainly have more than 20GB to 60GB of photos and home videos"
a family of four will also probably have more than one computer. you can pick up a 2TB NAS for about $150, that should be plenty of room for all their home movies and photos and it is accessible from all their computers.
a family of four will also probably have more than one computer. you can pick up a 2TB NAS for about $150, that should be plenty of room for all their home movies and photos and it is accessible from all their computers.