Saudi is under control as best they can get it, Iraq will now become a new source of terrorists no matter how the US tries to tame it.
Next is Iran.
Then maybe Syria.
There are some great reads available on US thinktank theories on the future developments in global terrorism that are well worth reading and give some insight into US tactics going forward.
Yes, control of oil supplies amounts to ensuring no other power develops to challenge US supremecy. Donald Rumsfeld and others such as Paul Wolfowitz have numerous articles on the public record speaking about their views on this matter.
They are looking ahead beyond so called retail and wholesale terrorism (suicide bombers and the World Trade Centre respectively) to a new level where sooner or later a nuclear device takes out a major population centre.