But Gates didn't invest in Apple to make money on the stock. He's much better served sticking with his own. As far as an investment goes, at this point, Apple is a sucker bet. Each year, they become more and more marginalized, and while the Titanium Powerbook has done well, it is off-set by the G4 Cube disaster.
No, Gates invested in Apple to insure that his investment in Office for the mac didn't suddenly go tits-up, and also to gain leverage with Apple's management. There was also the PR aspect, which was huge.
The mac's dirty little secret... the top software developer for them is Microsoft. If history is any indication, then it is only a matter of time for Apple.
BTW, if you read my post, you'd see I use both. I have a G4 that I use for Media100 and AfterEffects, and I stated that it is superior for graphics processing and manipulation. But on all other counts, Windows wins hands down. I'm not anti-mac, just a realist.