macs can get hacked, i'm not going to argue that. you need to secure your mac and your network, just like your windows machines. but i don't agree that the only reason there's very few viruses for mac is because more people use windows, or that mac users are lulled into a false sense of security. most mac users don't know why they don't need antivirus software.
Unlike Windows, Mac OS X applications don't share a common registry. Mac OS X applications use individual preference files, thus the types of global configuration changes which enable so much of Windows malware is simply not as feasible on a Mac. Further, on Mac OS X, the Web browser is not integrated into the operating system - it's a completely separate/independent application. This isolates the browser - a common infection point for Windows users - and helps insulate the Mac OS from external attack. Root access is needed in order for malware to interact with other programs (i.e. steal passwords, intercept transmissions, etc.) By default, root access on a Mac is not enabled.