Additionally, China has quite a wide variety of border disputes with nations that the United States recognizes as sovereign and independent of China. I doubt very highly that the US Pacific Fleet would be allowed to stand idly by, should China get it in its head to stomp all over Taiwan. Then there's the hornet's nest that is Korea that could indirectly draw the United States and China into direct confrontation.
Given the hopeless obsolescence of the majority of their military, the institutionalized incompetencies and the massive corruption it is highly unlikely they can win, or even force a stalemate if there was a direct confrontation.
I wouldn't be so quick to dismiss the Chinese military. In terms of attacking corruption their government is doing
better than India. Reducing corruption is very much a matter of economic development and authoritarian states like Singapore have managed to run a very efficient government since they began pulling the tax revenue to fund it. And although the PLA has done a poor job of producing skilled soldiers, China has enormous economic and manpower resources at its disposal if it ever needs them. Chinese steel production is over five times that of the United States. The PRC may have a small defense budget now, but it's industrial output is already sufficient to support a very powerful force when the time comes.
The main thing in the way of the reconquest of Taiwan is China's lack of naval power; the USN is about as powerful as the rest of the world's navies combined while the PRC lacks a fleet commensurate with the country's industry. The ROC is an island, and control of the nearby Pacific would be the decisive factor in a China/Taiwan conflict. It will be a long time before the People's Republic has the world's most powerful navy- but it will probably get there in the not too distant future.
With the F-22 in the sky, Russia and/or China would have to enter into a conflict with the United States knowing that they are technologically incapable of gaining air superiority.
Even with what we have today they are still incapable of gaining air superiority. Most of China's air force are Soviet designs from the 60's and most of Russia's air force was allowed to degrade so seriously that most of the fulcrums and flankers aren't even in working order anymore.
This is a valid point since China does not yet have a fifth generation fighter. By 2019 though they will likely have something. The J-20 will be a serious competitor to the JSF and PAK FA, but in terms of stealth and thrust-to-weight it is still no match for the Raptor. China is catching up- if nothing else, it's getting better at stealing- and judging from the development of similar Asian countries it will some day have a technological infrastructure comparable if not superior to that of the United States.
Of course China is too dependent on foreign trade to start a war now. But I could certainly see it acting more aggressively in a few decades.