Iraq: No doubt about it. Saddam has blood fued with the US.
SA: I doubt the Government per se was involved in 9-11, but rogue elements within the Government, and probably within the Mosques, probably including members of the "royal family", very likely were involved.
China: Hmmmmm. I have difficulty with a direct involvement of the government. Surely they are involved in arms proliferation and other nefarious activities to undermine the west. In that sense, they are in the same leage as North Korea, Cuba, and a few others who are interested in spreading Marxism. But they have WAY too much to lose with a direct involvement. Rogue elements within, perhaps.
PS: The Bush administration has been playing this masterfully, holding back on releaseing the damning intel while giving Saddam the rope with which he will hang himself.