The problem with modern day reliability tests of hard drives is that it is difficult to test how time affects drives. Running a drive for five years is not the same as reading and writing terabytes of data to a drive for a month. Voltage spikes on booting up a computer and vibrations from removing a drive from a case can't be mimicked in a lab.
Brand reputation doesn't mean a whole lot either. No brand that I've owned has been immune to the click of death or the high pitched wheeze that accompanies a dying or dead drive.
I've gone through lots of hard drives in my time. Thankfully, most have died after being decommissioned, or I was able to recover the data from them before putting them out to pasture. As a service to someone out there (and for my own record), here are the hard drives that have died on me.
Western Digital 2.1 gb. This is the first ever drive that died on me. The motor spinning it just got weak, and I'd have to give it a quick twirl in my wrist to get it in motion. Once in motion, it was fine for a short while. Eventually, I got write errors, so I put this drive out to pasture. I was glad for the excuse--it was by far the loudest drive I've ever owned.
Samsung 20g (SV2002H). I've always liked Samsung as the maker of the quietest drives. Unfortunately, they do have a reputation as unreliable drives. I'm 1 for 2 as far as reliability is concerned for this brand.
IBM Deskstar (IC35L040AVER07). I chose this one mainly for the performance reports from some online source. They were commonly referred to in the hardware community as Deathstars. This is the only IBM drive I've ever owned.
Western Digital (WD1200). I didn't buy this drive; it was part of a RAID config when it failed, so no big loss.
Quite a few Maxtor drives have passed through my possession, but surprisingly none have died.
The moral of the story is that all drives will die. Even you fans of Solid State Drive might one day be disappointed that your drive is dying (though I'd expect them to be more reliable). Run a back up system. For a while, I was running a file mirroring software over network shares, but that required me to be diligent about running it. Currently, I use a software package that backs up the folders on your computer to another computer on the network, which takes care of the two most likely reasons to need a backup - drive failure, and theft.