shift your cash, investments, and property slowly into international markets as you age.
While the international markets are hot that isn't going to last much longer. Vietnam's market is up 1500% for the year largely because people can borrow money to put into the market. Great deal until the market tanks and people can't repay the loans and then it is a downward spiral (see USA 1929).
China and India both have inflationary markets which will drive inflation in the US for the first time in almost 20 years. In China alone the salary of a factory worker has more then doubled in last 12 months in the Guan Dong province. This of course is finding its way into the cost of the cheap crap we have enjoyed purchasing for years along with fuel costs being out of sight.
The past 20yrs have been interesting because we have managed to hold costs down in the US by continually finding cheaper means of production. This lack of inflation has kept wages down as well. There is fast becoming no cheaper places and the costs to the supply chain in terms of security and fuel are further hurting matters (coupled with increased domestic demand in India/China for goods they have traditionally sent to us because they now have a middle class). All of this is going to drive inflation which hurts emerging markets.
Ultimately I think this will be good for the US and drive some manufacturing back here. You are already seeing it for low cost textile items like socks and underwear where it just isn't cost effective to manufacture and ship it anymore.
In short don't give up on America yet, we are actually in a better spot then most people think and as things go on I think that position will become better and better.