First, this is a distraction to the real conversation at hand, which is how secure will Windows Vista be on its debut. Is Windows Vista the most secure OS ever in a world of BSD, various flavors of *NIX, and OSX? I don't think so and I can't imagine anyone who isn't a Microsoft shill *cough*CNET*cough*ZDNet*hack* saying otherwise. Furthermore, because of the complexity of the code (which is why Vista is years behind schedule) and that Vista is actually Windows Server 2003 with additional code that Microsoft really has any idea how tough this OS is going to be in the real world. Obviously this is a PR statement designed to blunt OSX's stated advantages in security.
Second, people do attack Apache according to your ZDNet article in which an anonymous hacker described secret vulnerabilities that existed in OSX. Giving a local access account for your hacker is unlikely and stupid. So, I think we can safely say that the easily hacked OSX box was the result of poor configuration and a flaw in Apache rather than poor OS design.
Third, when comparing all the possible vectors for a malicious attack (viruses, malware, rootkits, vulnerabilities in services, buffer overflows, etc.) we can see that Windows has thousands of serious problems and comparing the same lists we can see that OSX has relatively few. The likelihood that all these problems are fixed with Vista seems unlikely at best.
Fourth and finally, we can argue for years about whether OSX is safe because its rare, tough, or well-liked, the safety of OSX exists regardless.
I expect at least one zero-day exploit within a few days of Vista's debut.