After occasionally wondering over the past 2 years whether spending money on extra drives to build a RAID 5 array in my desktop PC was worthwhile, I now feel vindicated after one of my drives (a Western Digital WD5000YS) failed over the weekend. Upon restarting my PC, Intel Matrix Storage Console was able to identify the failed drive, but it was impossible to actually use the computer due to constant delayed write error notifications and constant freezing. After noting down the serial number of the failed drive from Storage Console, I was able to remove the failed drive, and my PC is again working although the volume now shows Degraded status.
Even better, Western Digital have an Advance Replacement RMA program where the replacement drive is shipped immediately without needing to first return the faulty drive. They reserve the value of the replacement from your credit card, and this is not deducted as long as the faulty drive is returned within 30 days.