Here are some off-the-cuff possibilities:
"Photos" that are interactive "spaces" composed of combinations of many high-resolution images and (LI/RAY)DAR point clouds.
"Videos" that are the same or far beyond 8k
Individuals using constant-capture systems to archive their day-to-day, providing the ability to "never forget." This could be supplemented with local capture and storage of extensive biometric data for personal-health analysis.
Amazing graphics / texture sets to locally provide standard libraries for very high resolution AR / VR experiences.
Local archives of reference and web content so that it can be browsed privately to ensure privacy.
A general push-back against cloud storage in favor of local privacy. This might be powered by some federated system that allows individuals to give up some local storage in exchange for storage on other's systems.
120TB may still be more than you need for now, but 1-2TB in a gaming PC is now "cozy".
[1] https://www.theverge.com/2021/2/25/22302057/call-of-duty-war...
At the moment, I'm content with 14T drives for personal use, which is about 4x bigger than what I was using just a few years ago.
But if I had 120T, I would just start hoarding every bit of data I could get my hands on. I'm not quite https://www.reddit.com/r/DataHoarder/ level yet, but I could totally see myself heading in that direction.
And at $DAYJOB we need to store data in the order of magnitude of a petabyte. This also seemed huge just a few years ago, but now feels restrictive. 30x 120T drives to shove into a rack in the data centre would totally be considered if it were possible.
I remember in the 90s I heard someone ask how you could ever fill a 1GB hard drive ...
If you do any 3D work (engineering or artistic), the assets for these projects can be huge. If you're doing ML work training sets are massive. If you do more conventional development/content creation, software and assets needed keep getting larger with a never ending list of things to pull down from github etc. If you're just working with data/databases, the amount your working with never seems to get smaller and if it's time-based there's always more history to deal with as the years tick by.
Even if one does everything in 'the cloud', all you're doing is shifting the location of the storage needed rather than the quantity. So it's pretty much the same old story of 'more' when it comes to how much storage is needed.