One thing you are actively discounting are the China factor and the situation in Iran. Those two play a very big role in whether we are next on the hit list or a target in 20 years.
I am not discounting China and Iran factors. As for China, it seems to have some long-run goals and is not ready (at least before 2015-2020) to take on the West either politically or militarilty on a broader scale ( global or broader regional scale). Its strategy is best couched in the thoughtfully devised phrase like "peaceful rise" to power.
Further, Bush is on record to have said that Pakistan would be more difficult for the next president to manage than Iran, Iraq, or Afghanistan. Other American leaders like Obama and McCain have said they would shift focus from Iraq to Afghanistan and Pakistan. The way the Western media is projecting the terrirost threat from Pakistan-Afghanistan tribal region to the West indicates this area is primary focuss.
Iran is a problem but it seems unlikely there would be a war between West and Iran. It is likely though that Iran and West find some compromise solution to the issue of Iran's status and security in ME and Western sensivity to the emergence of an Islamic nuclear power in the Gulf region.