I used genres for organizing my movies. As a "fer-instance", The Sword in the Stone has for genres Animation, Children, Family, Classic, Adventure. I was reading up on tying a category to specific genre because I wanted to do something similar. This works for me because all of my movies are in a single directory called media, with each movie in its own folder. I'm at about 1100 movies on about 6tb and it works well for me (so far).