Best YouTube genre to date--better than 9 year-old karaoke wannabes and zit popping--is hands down "Literal" music videos where the song's lyrics are swapped out for a narration of what's literally occurring in the music video.
Since 99.9% of all music video happenings are certifiably insane, the results are hilarious. To prove my hypothesis, I've spent countless hours of scientific research--YouTubery, if you will--to bring you some of the internet's greatest examples of the genre. To wit:
Bonnie Tyler 'Total Eclipse of the Heart' (Literal Version)
Meatloaf 'Anything for Love' (Literal Version)
Journey 'Separate Ways' (Literal Version)
Tears for Fears 'Head Over Heels' (Literal Version)
A-Ha 'Take on Me' (Literal Version)