Right now I have 6TB of space in my desktop. I keep all my music and movies on the drive. DVDs are painful to watch, so I rip all of them to the hard drive then store the physical backup on a shelf. I have eclectic taste in music sometimes, so songs I own never get deleted for fear that they may never become available to me again.

Not to mention the massive amount of storage required for just a handful of modern video games (when they weigh in at 15+ GB each)

And take the case of a photographer who, with current equipment, can easily create 100-200GB of content per shooting day. (I'm thinking specifically of a wedding or event photog using a Nikon D800, Canon 5D Mk III, or similar class of camera. Besides the raw image files, there are the catalogs, processed/developed/retouched images, resized images for common print and display formats, album layout pages, and whatever else may be needed to provide the service offered.)