Will there be much effect on the US economy? I doubt it. The EU and the Eurozone in particular are not necessarily in big trouble as a whole. Balanced current account, that is something the US can only dream of. So any effect of European disruption is only felt on Wall Street, nowhere else. The real economy is not affected.
But wait a minute - at the end of the day there will be money wasted in Europe, either way of the Euro breaking up or not. That is earned money, real assets and will not be available for future investment. So the money will be missing for keeping up US economic status quo. In other words, it is not only China who pours in foreign money to keep the US running, some of the 2 Billion USD per day is coming from Europe and that money source will run dry.