Your proposition of banning some nationalities from the Arab world would achieve what the terrorists such as Osama bin Laden want, a clash of civilazations. The solution here with all due respect is not go back to tha dark ages of descrimination, but use our combined efforts to fight this evil. The vast majority of Muslems do not identify with Bin Laden, he is not voicing their beliefes and in fact they see him as a discrace to their religion which promotes peace and love. The lesson here is that the cloak of religion is a very powerful tool to fanatisize individuals. Humanity must stand up to this threat and not allow it to devide us but use it to unite the world to erradicate it.