back up your backups is right!!!
I still use 2 Western Digital drives, but I also had 2 of them fry out just in the last 6 months. Each time I instantly bought another one, and got right on the tedious chore of copying over the data to the new one (copying from drive to drive, through USB ports took forever, so I went from the remaining external hard drive to an internal hard drive on one of my fastest computers, and then downloaded back to the new external drive through a firewire port (use your fastest port... if you use USB, don't run through a USB hub)
...anyway, I'm damn lucky I didn't put off creating a second copy of my 500 gigs of backup after the first archive fried... because it was like 6 weeks later I had another dead "MyBook" on my hands. (for the record Costco replaced them both times... but I still wonder if I should get some of Marc's AcomData drives?)
I also wonder about the SATA connections on the back of the newer MyBook's ...I don't have a port to connect that way, but if I got a pci card with a SATA port, would this facilitate much faster transfer speeds then firewire?