I would prefer an old world tradition...Nail them to a cross.
The Romans perfected crucifiction as a punishment.
We on the other hand go out of our way to make cruel and unusual apply to the victim rather than the criminal.
I am ok with death by hanging. In many cases hang by the neck until dead would be more fitting.
For a particularly heinous murder(s)I would suggest impalement. Nothing like contemplating a large sharp stick slowly working it's way up through your body via the anus to deter people from killing others. As far as I am concerned the more painful the means of execution the better, and they should be televised in order that people contemplating a career in crime can see what is in store for them.
I wouldn't be adverse to having the families of victims being able to set the means of execution and maybe actually having an active part in them. Just sayin'.