On the China thing -- we'd probably end up in a nuke war if we were to fight China. We just simply don't have enough people to fight China in a conventional war, as they have like 3 times the population. I'm pretty confident that we won't fight a war with China because of the current focus on the ME.
The wars we have in the middle east are directly related to china.

I am not sure that we will be fighting an all out war anytime soon, but a cold war is possible. In fact, the approach the Bush administration is taking is like that. In a way, it's like defeating one country by invading smaller ones.