The reality? How much storage do you really need?
Not counting OS, etc, how much personal storage do you really need? How many songs and videos do you really keep?
Personally, with Netflix etc online now, there is ever-declining need to actually save movies. Not to mention I can listen to songs again and again, but watching the same movies over and over is a drag. Perhaps 1 TB is more than enough?
I have an Apple Fusion drive (128 GB SSD plus 1TB disk) and it's about half full, mostly movies. The 128 GB SSD is mostly operating system, applications and work files - I don't bother to keep movies etc there.