The most dangerous Sith is one that is not out for power, but out for a goal that they believe is worth dying for. Your list is pretty cool, but none of them will die for their own cause. When a person is willing to die for what they believe in, that means they will do everything in their abilities to carry out their agenda.
Revenge is a powerful modivator.
R.I.P. to 'The Source' and 'MacCorp'