I discovered this little exe,
http://madebyevan.com/diskitude/
It's pretty simple, and interesting at the same time... I probably won't use it ever again, but it gives an interesting perspective of how your computer is being used.
Here are my results:
As you may notice, I have two disks. Because this build is relatively new, I don't have that much data stored.
Pretty cool stuff,
Missxu