david.emery notes the release of Intego's "Year In Mac Security" report
(PDF), adding: "Mac OS X and iPhones that haven't been jailbroken fare pretty well (although vulnerabilities exist, there's not been a lot of exploitation). Apple does come in for criticism for 'time to fix' known vulnerabilities. Jailbroken iPhones are a mess. The biggest risk to Macs are Trojan horses, often from pirated software."