Now for an investing idea. Recently, I wrote a long piece about Steve Jobs, Apple and AAPL, saying, “AAPL’s best days as an investment are over. In fact, AAPL is likely to underperform the market in the years ahead.” Today, the stock plunged on big volume through technical support, following the news that Steve would take a nearly six-month medical leave. So my timing was lucky. And my conclusion is unchanged. Remember, it’s all about changing levels of perception. Your job–and ours–is to find the next AAPL. One way to do that is to ask, “What company serves a...