Here's what I normally watch on Youtube:
1. Anime
2. Music (heavy metal, hard rock, industrial metal, metal metal metal)
3. things about martial arts (training videos, Bruce Lee, etc)
4. Paranormal (UFO's/aliens/crop circles, and ghosts, everything else paranormal is just kind of blah, I don't really accept, but these two, I think there might be something to them)
And that's about it.
EDIT: I forgot one: 5. Stand-up comedy.