On a day when everyone was reacting to Bill Gates' announcement that he'll be retiring (Peter Cohan was happy, while Michael Rogers told us it was part of a plan), the Street buzzed about how Ray Ozzie and Craig Mundie would inherit Gates' mantle, with strong leadership from J Allard, Steven Sinofsky and Bob Muglia, and rumors of a Microsoft iPod killer resurfaced, Microsoft stock moved hardly at all. It ticked up three cents to close at $22.10, still very near its three-year low. Volume, however, was extreme at 50% better than average.

So investors are paying attention, and they're acting on the news. But I'm starting to agree with Michael: Microsoft is a widow-and-orphan stock, owned far and wide but not as much by technical, analytical investors. It's safe, and whether Bill Gates is at the helm; whether the company's video players are better than the iPod, or not; whether it spends $2 or $3 billion on operating expenses this quarter, generally, we can bet that Microsoft will continue to rake in the cash and conquer the mass market with its ubiquitous software and services.

Last week Microsoft's Bill Gates expressed regret about being the world's richest man. When I read this, I was reminded of the expression, "be careful what you wish for, you might get it."

Before launching into an analysis of how Gates could be toppled from his throne, it's worth noting that I've admired Microsoft and wondered whether it's lost its elbow room. I praised Microsoft's ability to adapt to change in two of my books, The Technology Leaders and Value Leadership. But in the last several years, Microsoft seems to have lost its mojo as I noted in these interviews by Red Herring and The Washington Post.

Here's a surprise. The biggest threat to Gates's top rank on the Forbes 400 comes not from the number two on the list, but from numbers 15 and 16. According to that September 2005 list, Gates's net worth totaled $51 billion. Berkshire Hathaway's Warren Buffett came in second at $49 billion. And he was followed by Microsoft co-founder Paul Allen ($22.5B), Dell's Michael Dell ($18B) and Oracle's Larry Ellison ($17B). Spots six through 12 were occupied by descendants of Wal-Mart founder Sam Walton, Microsoft CEO, Steve Ballmer, and heiresses from Cox Enterprises and Fidelity.