I would go for some kind of music that doesn't really belong to one genre. Say for example if I choose Amon Amarth as my choice, that means I choosed music that belongs to symphonic death metal genre and that would make the video watchable only by those who like that kind of metal. I like metal but not death.
My point is that we should search for some music that belongs to any specific group.
Not music that only is techno, not music that only is rap/hip hop, something that doesn't just satisfiy the listeners of that specific genre. Maybe I am being obvious about this it is after all the reason why this thread exists. To find music everyone like. Guess I should browse me media library a little...