I've used over 100GB before. Mostly music, movies and ISO images (Windows and Linux OSes, Software and Games). I like to have a digital copy of just about everything, just in case. Most of my movie (avi) files are around 1.5 GB, and the ISO images are usually a little more than 600MB... and I have over 30GB of music stored right now (mp3), and that's not even close to the amount I've had in the past. So, yeah, I can see how someone would want a TB of storage.