Sligslinger, I'm not going to steal your idea, besides, who wants to steal lame ideas anyway?
Mudokon, you are basically listing all of the LEAST original sites I can think of. Animal rights and petsites are some of the most numerous on the net. Music, Art, and Film are about the only types of website where it doesn't matter how many others are already out there, if they are fans of your work then they will come.
My suggestion to you is that you browse the net for things that interest you, and take note of all the searches you do that turn up little to no results. Those are your potential areas of originality. If you can be the first to make the best match on the search engine you use then you will achieve that originality, and you will get all of the traffic.