My homepage directory is split up very clearly, and it shows in the organization of this site. I have a procedure for downloading new software and installing it, then deleting setup files and backing up the original .zip files. But it's representative of my personality. My computer's very streamlined, only containing the stuff I actually use, whether it's system utilities, games, or whatever. People who are interested in sports will usually have subdirectories somewhere containing images of their favorite sports figures or articles from past newspapers.
Programmers have whole enshrined directories to each of their language compilers.
It's interesting to see how a part of someone's life ends up as a part of that person's hard drive. Other peoples' personalities shine through just as well. People who don't care for organization will just let files sift into wherever they end up. Hey, whatever lets them read their e-mail and play solitaire. No problem with that.