Yea that is a cool drive, Tigerdirect.com has the My Book Premium here:
Western Digital MyBook Premium 500GB 3.5" External Hard Drive - 7200, 16MB, USB 2.0, Firewire 400 WDG1C5000N at TigerDirect.com
For some reason, though, they listed the Essential and Premium at the same price.
But if the only thing you are doing with the drive is backing up your computer, then this is the better bet, a WD Passport drive, more than enough space to back up everything onto your computer and then some, very portable, easy to use and half the price:
Western Digital Black Passport 120GB 2.5" External Hard Drive - 5400, 2MB, USB 2.0 WDXMS1200TN at TigerDirect.com
And if you are curious as to what I was talking about concerning network
drives as opposed to the cheaper external drives, take a look at this:
Western Digital MyBook World Edition II 1TB Network Attached Storage (NAS) WDG2NC10000N at TigerDirect.com
Anytime you have two or more computers hooked to a router (wired or wireless) you have a network and would benefit from a Network drive. Again, they can be used exactly the same as an external drive, or hooked to the network allowing multiple users to access them and back up to them. With 2 500gb HDD's two people can access the drive at the same time, each with their own drive to back up to and use as general storage with more than enough room left over.
Mine has 2 500gb drives and a DVD burner in it. Since I use DVD+RW disks, I can re-use the same ones over and over. I have 4 laptops connected to my home network, two users to each drive (for now, it has 4 bays so 2 are empty right now). The system automatically does a back-up of each computer once a week, then once a month it burns full images to the DVD+RW. I keep 12 DVD+RW disks, so I go back a year before I over-write a disk, and I use DVD-9 DL disks so it all fits (after compression) onto one disk instead of the usual 2.
Anyway, probably more than any of you cared to know, LOL. If the only thing you are looking for is to back up only one computer easily and without much though, go with the Passport style external drives, 80gb and up depending on how you are backing up and how much data you have. These are 2.5" HDD's so much more portable than the larger desktop drives, some you can just slip into your shirt pocket and off you go!