MP3 Organization

I've done some searching and haven't found an answer to my technical question and so I was hoping you two geniuses would have some tips:

I have 10GB worth of MP3's, with about a third of it being my girlfriends music (>.<)

I would like to be able to create on the fly playlists from the MP3's themselves without having to manually select tracks. As a good analogy, think of how GMail's labeling function works. I want to be able to assign multiple labels to each track so that no matter what player i'm using i can create playlists based on those labels. Does that make any sense? Is this a thing? If not it should be... 

Thanks for any insights you guys might have.




Well the label thing would be "genres" or whatever, but tbh i'm not even sure what your asking for, is it a mp2 player or?