As one of the few (and proud) folks out there with more than 17 years of network security experience, I find the notion of "Windows Security" to be oxymoronic, and laughable at best. A few years back, I was asked to build a "hardware security device" for our first (management mandated) Windows server, when placed on the same "red zone" as our mainline Unix boxes. The "device" was little more than a coaxial cable relay, controlled by a more trusted piece of software. Of course, Linux is only slightly better, but then Linux isn't the only (or even best) open source Unix out there.
As for Microsoft's "innovation" and "support" of open standards, most research-grade CS folks have quite the opposite opinion -- that Microsoft stifles innovation through it's copy-and-sue-us practices (which kills most VC funding for software startups) as well as the "embrace-extend-kill" strategy which has worked well for them in the Browser Wars as well as OS/2 and the killing of Java thin clients.
It pains me that, in spite of this, they are more or less a US company, and the US economy does get some short-term benefit from their dominance of the software industry. But already, Microsoft is moving their "research" and development jobs from the West Coast to India, and with Bill going gaga over China, you can bet they'll be employing more people there soon.