It's impractical and unrealistic to expect any technology to be failure proof, particularly when it comes to hard drive storage. CDs and BD can fail too, so can tape backups. I manage enterprise drives (IT Admin) and I can tell you that although HD failure rates are lower overall, there are failure nonetheless and they're never timely. I've had Seagate and HP SAS drives, $300-500 drives with very low MTB failures, go belly-up on me within a month of implementation as well as within a year or three. Yet other drives have been on 24/7 for 7 years and they're still cranking.
That said, this is the reason why you want a RAID 1 or RAID 5 setup - redundancy so as to minimize downtime. One drive goes down, you can remove the bad drive and replace it with a new one.
At home I run RAID 1 for my OS plus RAID 1 for critical storage, plus a backup system. I also have a tool (Crystal Disk Info) running to check the SMART status and temperature on all my drives of my home server (4 internal and 6 external). As soon as I see anything get flagged, the drive gets replaced (usually under warranty).
My recommendations in general are:
a) If you don't want to build your own but need an out-of-the-box solution, get a NAS storage with at least 2 or 3 drives you can use in RAID configuration. Buffalo Tech has some very capable boxes (I use a 3 TB linkstation at work for ISO storage). Seagate, Western Digital, and Drobo are good too (Drobo but tends to be pricier for what you get comparatively speaking). Look for at least a 3 year warranty. Stick to RAID 1 or 5 for redundancy.
b) If you're tech savvy and want to build your own, buy SATA RAID cards and enclosures with eSata capabilities and build your own RAID array. Drives usually have 3-5 year warranties so look for external enclosures with at least that much warranty. OEM externals typically only have 1 year.
Also, download Crystal Disk Info (
CrystalDiskInfo - Software - Crystal Dew World) and run it on your machines.
Lastly - RAID is not backup, it's redundancy. As it's conceivable that a full RAID array can fail (it happened to me when the RAID controller corrupted all drives in the array), you need to backup your files to an external source, whether you use DVDs or another hard drive or two. The more critical your info, the more backups you should have.