To get straight to the point and leave all the rivalry aside, let's fast-forward the Gates VS Jobs flame war.
Setting that aside, here are my thoughts on Bill Gates's retirement from Microsoft:
Bill Gates' decision to loosen his grip on Microsoft so he could focus more on his philanthropic ideals is not a surprising thing for me. All men who reached their billions at a considerably young age tend to look for different ways of fulfillment. Most contribute to noble causes like fighting AIDS, Cancer or poverty. In Bill's case, he vows to actually concentrate on that rather than just contribute.
So what will happen to Microsoft?
Well Bill Gates is going to leave his baby to Steve Ballmer and a team of executives including Craig Mundie and Ray Ozzie.
I doubt that anything drastic will actually happen to Microsoft. One of the worst things just transpired with the Yahoo-Microsoft negotiation fallout and unless Murphy's law works on billionaires (which I highly doubt), Microsoft wouldn't experience anything devastating anytime soon. It's still too early to predict what would happen in the next few years but it's safe to assume that Bill Gates wouldn't totally leave the company. He'd still be there, we can all count on that. If you're one of the founders of a multi-billion company, you wouldn't totally leave it regardless of how much money you already have.
Oh and because I'm such a big sap, I just have to put this little snippet in:
Ballmer said he almost quit soon after joining Microsoft because his parents didn't want him to drop out of Stanford.
Gates responded: "You don't get it. You don't get it. You don't get it. We're going to put a computer on every desk, in every home," Ballmer said.
(now doesn't that make you go... "aawwww...." ?)