Well, I think the debate would be in the business realm. There were still applications for the large tape carousels when I left .gov. For home users however, I think cost and convenience make external disk, NAS, etc. storage more practical for most users. I consider myself a fairly heavy user of data and I still backup to a 4TB drive with room to spare. I do keep music, and images from my D300, on a separate drive, but two external USBs are still way cheaper than a good tape system. For those with big bandwidth at home, cloud backup is another relatively cheap solution.
Also for catastrophic stuff, an external USB drive will be much more practical than tape. Example = evacuate the house due to fire, earthquake, etc. It's easy to grab the USB drive, and it will then just plug into whatever computer you have handy if you have important files you need to access.