I firmly believe Windows needs the competition. Without competition from others for market share Microsoft will stop listening to critics and will become fat and lazy. (not that they are not already fat now) They are certainly not lazy now, but if they don't have someone to measure against, they will surely slow down and become entrenched.
I just am so tired of "Linux is more secure" statements when it is clearly not the case when looked at objectively. The number of published PoC viruses, exploits, CSS attacks and directory traversal attacks is far more numerous for Linux/Unix than for Windows. Windows systems have the distinction of being susceptible to really dumb, simple and often very obviously preventable vulnerabilities that make the numerous targets very tasty to those with ill will or a point to make. I look at the vulnerabilities lists and I see patch after patch and often patched patches for kernel versions and applications and often essential services in Linux/Unix systems every day.
Fedora Core is now in it's 5th major release after only 1 year in the marketplace. Yes, it's free, I love free software, I love having source code, I enjoy twiddling Linux when I don't have serious work to do and can learn from it. Just don't tell me it's more secure out of the box or that it's easier to manage or a useful system for computer novices, because it just isn't so.
I own an iMac. It's still running OS/X because that's why I bought it, to learn OS/X, not to run Windows on it because I already have 4 PC's running Windows or Linux already. I can also tell you that OS/X ain't all that secure either and isn't exactly easy to use if you go outside the domain of ready to use pre-packaged applications.
Microsoft has brought a very easy to use and very complex system to the market and they deserve credit for all that it does. They also deserve every bit of criticism when they do really dumb stuff, like the WMF bug, but the *nixes have their bugs and root kits too, so don't be too religious about your *n*x OS. Remember, the term "root kit" comes from the first root kit, developed against a *n*x target to gain "root" access, not "administrator" kit.
It is also no accident that many applications are developed on Windows boxes with Windows in mind and then later ported to OS/X or Linux. The real money is to be made in selling to Windows users, not Linux users who like me, want it all for cheap.