thank the computer Gods that mass storage is so cheap these days. Who could have dreamed a few years ago that multiple terabytes of capacity on a home computer would be feasible!
I tend to keep most stuff that I amass, even if I don't particularly find it all that appealing or exciting, because there's bound to be someone else out there who is looking for it.
I really don't know how much porn I actually have, but I could conservatively estimate that I would have no less than 150 GB of pics and many times more than that of video. It's quite scary when you stop to think about it