I don't understand why this thread has drawn such little attention. My observations of the investing behavior of perhaps the majority of those who post is that it favors the old buy-and-hold, stocks-for-the-long-run mantra. While I also tend to hold my investments for periods of five years or longer, a few caveats are in order. First, the typical small investor continues to hold on average only 10% of their equity allocation in foreign stocks. Also, a truly diversified investment portfolio holds the sorts of asset classes encompassed in, for example, the Harvard and Yale endowment portfolios. These guys are the ultimate in long-term investors. It's an endowment, after all. If you are not familiar with these managers' investment strategy, Google them to learn how they define reality.
If you haven't done so already, please broaden your definition of diversification. The underperformance of US equities has been appalling.