I disagree.
Syria is a problem, but they are NOT the center of terror.
They are weak and just left Lebanon to the Iranians and Hezbollah.
Syria is so weak that Janes Defense Weekly expects a coop soon. The Iranians want to see a change there and are in a position to cause trouble there also.
Condi Rice herself said that Iran is the #1 terrorist nation in the world. Which is exactly correct. Syria is Iran's pawn, and Lebanon is Syria's pawn. Then you have Hezballah and Hamas, etc., that are paid by Iran. In an idealistic scenario, you eliminate Iran, then you also neutralize Syria and Lebanon. Which could help lead to peace in Israel. But you have the Saudis and their Wahabbi Islam and its strong connections to al-Qaeda.
Point is, you get rid of Iran, then you will have acheived an enormous victory. Though you still will have problems, no doubt about it.