Malice is the Windows King around here. I rule Mac World. He and I have worked together to help many a person with a problem. He would agree that Unix, Linux and Mac distro's are much less succeptible to viruses and spyware because their security model is inherently better constructed than Windows and that they don't have the vulnerabilities presented by Active X and other architectual deficiencies that Windows has. It's not to say that they are immune to viruses or spyware, but they are much harder to code for. There have been roughly five proof of concept viruses for Mac OS X in it's six years on the market that never really got released into the wild because they are too difficult to make replicate and proliferate on their own thanks to the security underpinnings of OSX. It's also incredibly difficult to make them deliver a devastating payload. Social engineering through tricking people into entering their root level access passwords on OS X are really the only way to get viruses or spyware onto a system and even then there are some inherent issues. I've seen the script kiddies talking about this on hacker forums and they're damn confuzzled about how to write an effective OS X virus, but it's not for lack of trying. Last I looked, there are over 150,000 Windows specific viruses in the wild and I don't know how many pieces of spyware and malware.
jag