On an external drive such as the Western Digital MyBook 500GB, does the 'single click' backup feature literally backup EVERYTHING across multiple drives - i.e emails, files, bookmarks etc. across all your hard drives? I'm looking for something that is pretty foolproof in this regard and allows for backup of literally everything quickly and easily across 3 hard drives (total potential capacity of just over 400GB, although realistically closer to 300GB). Is that possible with an external drive like this one, or am I living in dream land if I expect to find such a product!? 