At work we have a 10TB server that's half full.
At home I have 2 x 2TB drives. One for movies and tv shows, the other for personal stuff and music. I've got about 800gb of personal stuff, half of it is projects, photographs and raw movie files for advertising (entire portfolio).
You go on to say that you have a 120gb drive that isn't full. This tells me you either don't do any work on your laptop or only do work that's mostly emails and text.
I don't have a laptop. I have an early 2009 Mac Mini, which I use for work as a teacher (mainly Pages & Numbers, the odd downloaded app and Internet, plus iTunes along with Garage Band to digitise audio from tape) and personal use (more of the same plus photography).
He either shoots in JPG or doesn't take very many photographs. Either way, it's ridiculous to question how people fill multi-terabyte drives.
Why the ridicule? Does it make you feel smugly superior, or something?
Which sort of camera and image format do you use? Are you working with RAW files at the maximum resolution or something less demanding?
I use a Fujifilm X20, at the maximum 12 megapixel resolution, saved as JPEG files, and edited with iPhoto. Nothing flash, but as an amateur photographer the X20 was within my budget, and suits my style. I'm not deeply into photography as an art or anything.
I do take quite a few photos, but cull heavily, keeping only the ones that tell a story……
Hence I do not bother with archiving a large number of photos that will be of little interest to me or anyone else.
Yes, a better camera would get better shots, but to make the most of it I would need a computer with more grunt to run better apps, and more storage; all beyond my budget at present.….. Even I did the upgrade, I would still only be keeping the most interesting photos. I doubt that I would be needing multi TB storage.
I do have some music from CDs on iTunes, but mostly I listen to music on the radio, or at live performances.
Can't see the point of storing movies as some folks seem to do, in large numbers. While we do listen to a piece of music many times, we don't tend to watch most video content repeatedly.
Video is not a big part of my life anyway. I don't have a TV. If I want to watch sport, I go to a pub. For movies, I prefer the cinema. I used to sometimes rent a DVD, but they are gone from where I am at.