I just had a HDD fail on my iMac. I was backing up via time machine to an external WD 750 GB drive that I put in to service at the same time I got my iMac. I went to plug my External HDD directly to my MacBook after I took the iMac to the Apple store, because I use the same one for all of the computers, just on different partitions to back up and the HDD was dead. I want to know if anyone else has had two drives die at the same time? If so how can I safeguard against this happening again? BTW the drive in the mac was a WD 320GB.