If you wrote the Divine Comedy...?

In the Inferno, which sin would you have considered the worst? If you don't know the book the sin that's frozen in the last circle with Satan is Traitor to Benefactors or Traitor to someone who only ever tried to help you. I think that's pretty good as the WORST sin but I probably would have changed the order of some of the other ones. And I don't think there should be a Limbo, those people should go to heaven!