I use to collect porn videos and pictures, but then it became too much of a hassle to always be downloading them, not to mention they take up way too much disk space so I just started watching/viewing them then deleting after. But at my peak, I'd say I had about 300GB worth of videos and pix.
With internet speeds being so quick, there is no need to cache much for the long term. DVD's worth can be downloaded in an hour, then scrap them and start all over the next day!
I have about 800GB of porn on an external thats just for porn... I dont delete and dont put on DVD...just keep it on an external... and it grows everyday