Arafat and Saddam to my knowledge are not Muslims but secularists. Bin Laden may be a private Muslim person but is unqualified as a Muslim leader as explicitly stated by Mullah Omar himself: http://www.upi.com/ [broken link]
Some Ayatollahs may have the opinion to say but not their principal leader at this time, the president of Iran who is one person of wisdom and moderation worth a million Blairs and Bushes. As for Hamas, they are the product of Israeli terrorism. Remove the latter and you will cut their lifeblood.
If you are seriously interested in the true Islamic position on terrorism read: http://webpages.marshall.edu/~laher1/TERRORISM.HTMLPeace to those who follow guidance. Hajj Gibril