
Sorry, old son. Mustn't pretend to be superior without criticising Windows. I'll make a note of that on this here Post-It with my password on it (as if) and I've used the Evil Bill icon just for you. Doesn't that make you feel just dandy?
Any fairly modern (>NT5) Windows box is able to arrive at a state approaching the impregnability of any other OS given the right TLC. Disabling unused services making the possible malware ingress vector surface smaller, accepting sensible defaults and overriding those that aren't, removing admin privileges from ordinary users, paying attention to updates and security mailing lists (yes, ElReg can be useful, too), limiting the software installed or installable by users to a subset of well-tested and trusted applications, use of group policies and access controls, auditing third-party software packages for published flaws, ingress and egress filtering on the gateway and so on.
There are no design flaws in Windows that cannot be mitigated with best practice, just as there are no safeguards in *any* operating system that can mitigate poor administration, lack of maintenance and user fallibility. What has killed Windows' reputation with regard to security is a combination of a massive install base to target, the *vast* majority of Windows instances being run as Administrator by users sans clue at home (UAC is no substitute for the user having to beg someone with nous to install the latest BonziBuddy clone or crappy browser toolbar) with various crapware (Dell, I'm looking in your direction), spyware and P2P applications installed and, finally but most prevalent where Windows is troublesome in a corporate setting, incompetent "systems administrators" and clueless users. Those saying otherwise have never studied and used the Windows OS in the depth required to arrive at this relatively secure state which is the crux of the issue, unless you want to include those who think that for [insert OS here] to win, Windows has to lose (was it Jobs who said that about Apple fanboys criticising Windows for perceived but false issues? I forget).
Please, do remind me which was the first OS to fall in the last "Pwn2Own" contest, too. You would think that, with all the "fundamentally flawed" design decisions in Windows, it would be Windows and they wouldn't require user intervention, a browser or Adobe swiss cheese-ware to accomplish it. Perhaps they just didn't want a Sony Vaio and five grand? As it was, Safari failed epically, maybe because the MacBook was a more desirable prize. Yet again, a user-space application combined with user activity compromising the operating system, which was exactly the same way the Vista box was compromised in the next slot. Same shit, different OS.
Are we done with this debate now or, as the French would say, shall I taunt you a second time?