A NAS/Fileserver is the most reliable as it allows for redundancy. Lets say you have 4 HDD's in RAID5. One drive can fail, then you can just replace it and the RAID will rebuild the file structure as if nothing were ever lost. RAID 1 takes two HDDs and mirrors them.
QNAP, Synology, and Western Digital Sentinel are great picks there if you need dead reliability.
If you're looking for just some media storage that you are hoping won't fail, WD Caviar Black is a good way to go. If you need it to not fail, you should have two in RAID1 at the very least.
Perfect. Thank you!