I have my own computer (Windows 7 btw) so I don't have to worry about people throwing around their stuff. I have a "Website" folder in My Documents were I keep all my files that have anything to do with MPL. That thing is around 172 GBs. 
I also have a "My Games" and "My Programs" folder where I place programs or games that I don't want installed in the Program Files. Downloads download directly to the "Downloads" folder. And any files I am currently working on or editing are saved to the desktop. Then I have a major clean up session where I sort and delete all the junk on the desktop. It looks like this:
I also have a "My Games" and "My Programs" folder where I place programs or games that I don't want installed in the Program Files. Downloads download directly to the "Downloads" folder. And any files I am currently working on or editing are saved to the desktop. Then I have a major clean up session where I sort and delete all the junk on the desktop. It looks like this: