Most dangerous:
- Any leader of a country with nuclear weapons, or other WoMD. This includes Bush, Putin and Jintao amongst others. These I only view as potential dangers as I don't believe neither of them are interrested in causing trouble.
- bin Ladin. Fanatic troublemaking terrorist.
- Kim Jong-Il. North Korea appears almost paranoid in my eyes, and if they have nukes too...
Being dangerous generally also mean that you have a certain power and influence (not neccessarily political power) so anyone who fits those criteria can be potentially dangerous.