Yea, China could take Taiwan... and if they couldn't they might just nuke off right off the map. Dunno what the prevailing winds are like in the part of the world, fallout might make that an unattractive option.
I'm not sure how many people are actually aware of the fact that within 20 years, the U.S. will no longer be a economic "superpower".. it will be Asia's turn.
We'll probably still be a military superpower, I really can't imagine the United States politicians ever giving that up voluntarily, although it'd be something if China put us out of business the way we put the Soviet Union out.
Pretty much any major war between two nuclear countries will result in one country ceasing to exist. Maybe both, but definately one.
In my opinion anyway.