Got 4x1TB Hard drives on a Linux server setup using ZFS as the file system. Basically RAID-5 without write hole issues.
I don't envy people who have single 3TB drives and stores all their data on them. That's a lot of data to go missing if the drive suddenly dies. RAID isn't a backup solution area but it's better than nothing, and ZFS is a better solution over RAID any way.
I store everything on my PC with copies of my videos, music, pictures, install files etc. copied to my NAS (Netgear ready NAS, suits my needs) with the important stuff like the family photos in the cloud to share with friends and family and of course for DR. Everything else can either be recovered or not that important.