It is interesting to go to security conferences where zero percent of the laptops run Windows. The mix tends to be 70% openBSD and OS X is next in line. Windows, by its popularity, is target number one to those who would cause problems. There is a general agreement that most of the attacks to date have been the work of amateurs, but more serious people are beginning to get involved. Several of the world's top security people basically say that no business or government should put invest in a monoculture if they wish to operate smoothly in the future. There are many non MS environments that can be used, but Mac OS is the only one that supplies a desktop useful for most people (hopefully Linux will continue to improve along with free and open BSD). When the serious guys get involved many Windows users are going to have very interesting problems. Microsoft and Intel are approaching this by moving to a very hard form of security that locks down the hardware. It will give Microsoft (and potentially the government) an impressive level of control... of course everyone trusts Microsoft to not abuse this:-) Niches can be important. Note that Porsche has less than 0.2% marketshare and clearly doesn't have the number of cup holders or the ability to roll over in an accident that appears to be necessary for success in the American market. They are horribly overpriced and the technology of the lower priced models is fairly old. I'm noticing the folks who are hardcore Unix users are moving to OS X Macs in numbers that are surprising. At some level you buy what you need and what doesn't stand in your way.