i dont have that big of a system but i built it due to umedia and kids photos /videos
i rip all my movies to my hdds as i am too darn lazy to walk down stairs to get them, bow i can just point and click.-- i went with freenas because i like the redundancy and corruption avoidance - with our first kid on the way i want to be able to save all the moments and not worry about them, -- with that said i WILL have several backups >;o