My Seagate 3TB (ST3000DM001) is still going strong, which is mainly used for non-critical data, such as temporary video recordings. It currently has 8759 hours and still showing a good health status in CrystalDiskInfo.
The longest running hard disk I have is a Western Digital RE4-GP 2TB (WD2002FYPS) with 27,458 hours, which is my main data hard disk.
My workplace has a server with four regular 80GB SATA Maxtor hard disks that has been running 24 hours a day since 2004. Although I had bad experience with Maxtors and even had an 80GB desktop HDD fail, that server is still on its original 4 hard disks (2 pairs in RAID0) and in good health status the last time I checked.