http://what-if.xkcd.com/23/
Read the bit under the heading "How much physical space does the internet take up?" It is surprisingly small.
I think this is the big push towards cloud storage. If we can get file recognition software fast enough to know when there is a duplicate then there is great potential to have a 'global' file system which houses all popular bulk media (video, audo, pics, etc), so that there is 1 (extremely backed up) copy of things to be streamed to end-users instead of each and every user having their very own copy of everything they like and enjoy. Meaning one copy of the lord of the rings trilogy taking up some 40GB of glorious HD footage on a server, compared to 1000 users eating up a collective 40TB of space.
As I get older and now have drives full of pics and vids of my own life and kiddos, I am loving services like Netflix more and more. Give me a small monthly fee, and when a new HD version of something comes out then I already have access to it, rather than buying the VHS, then the Laser Disc, then the DVD, then the BlueRay, etc. I guess the only problem is that Netflix does not have everything I would like to watch.