The only certainties in life, the saying goes, are death and taxes. But for IT pros and home users alike, there has been a third one for the past three decades: Bill Gates as the leader and public face of Microsoft, the software vendor he co-founded 33 years ago.

Along with Apple CEO Steve Jobs, Gates is one of the two most seminal figures -- or at least widely recognized personalities -- from the PC revolution that eventually begat both the dot-com era and today's Web 2.0 movement. And because of his fabulous wealth, and all of the controversy that Microsoft has generated because of its market dominance, Gates may be the only IT industry executive familiar even to members of the general public who aren't at all tech-savvy.

But the certainty of Gates being at Microsoft is about to come to an end. The 52-year-old will officially step away from his day-to-day role at Microsoft at the end of this month in order to devote more time -- along with his wife, Melinda -- to the charitable foundation that bears their names.

William H. Gates III's legacy within the IT industry no doubt will be colored by people's views of the company he has built. Obviously, there have been a lot of pluses: directly or indirectly, Gates has helped to bring computing to the masses and to enrich hundreds of thousands of Microsoft employees and business partners, plus many more shareholders. In addition, he has played a large role in helping the US maintain its position as the global leader in technology.

But his detractors -- and there are many -- say that under Gates, Microsoft has overcharged tens if not hundreds of millions of customers while afflicting them with, umm, less-than-stellar software (see David Letterman's backhanded tribute video here). Critics also contend that Gates engaged in monopolistic business tactics both in the US and overseas in order to crush challengers and amass one of the largest fortunes in the world, worth an estimated US$58 billion.

It also seems like Gates has been retiring for a long time now. Microsoft announced on June 15, 2006, that he would immediately give up his chief software architect role and then stop working full-time at the company following a two-year transition period. Since then, Gates, intentionally or not, has taken more victory laps than Formula One driver Michael Schumacher did in his racing days.

In particular, every public appearance by Gates over the past 12 months has been touted as his "final (fill in the blank) ever" -- until, inevitably, he shows up again somewhere else.

What has helped make it tolerable is Gates' willingness to poke fun at himself. For example, he was self-deprecating enough to star in a celebrity-filled video spoofing his retirement plans -- and as corporate videos go, it actually was funny.

Despite all the talk of retirement, Gates won't truly be gone from Redmond. He plans to continue as Microsoft's chairman, and he said last week that he still plans to spend 20 per cent of his time working at the company on projects involving technologies such as Office and search tools.

So he won't be history, really. But it is a good time to start thinking about how to judge Gates and his impact on the IT industry from a historical perspective. During the course of this month, more stories will be published examining his legacy and analyzing Microsoft's prospects in the post-Gates era. You also have the opportunity to weigh in with your thoughts and opinions on those topics, via the reader comments section lower down on this page. We'll call attention to some of the best comments in a later story.