"Simply secure" with Apple.

One of the things that I enjoy about using UNIX OS is the security and protection from viruses.

Before I became a MAC user I had many incidences of virus infection on my PC. Once I even received a message from the U.S. Department of Agriculture, telling me "...Stop infecting our servers... and hacking into our network...' I paraphrased. While I had never even visit their website!
Next thing I knew, was that my computer was long infected and was being used to infect others. Finally when the antivirus software detected it ... the computer went mad. After a long battle with the virus and trying many software to cleat it, my PC was operable again but its window messages were mixed up!
How? For example, when it was asking me " Do you want to save this document? Cancel/OK
OK was cancel, and Cancel was OK!!!!
Imaging what did I go through before I figured that out... I think I started loosing my hair then...
I even tried to donate that PC to the Salvation Army, but they did not take it!

For a few years I was computer free at home and lived a happy life until my wife (who was my girlfriend at that time and was and is a Techie) lured me to get a computer again.

This time I converted to Apple and I am very happy about that. My computer is 5 years old now and still works like a charm .

Here is a little article on apple security for OS X.

Simply secure.
The Mac offers your organization a simple way to protect critical data and systems company-wide, with out-of-the-box security that’s easy to maintain and customize. Built on a proven, fully-compliant UNIX foundation, Mac OS X Leopard and Mac OS X Leopard Server provide layers of protection that are built-in, not bolted-on. This means your organization gets in-depth security at all levels of operation—from hardware to operating system to applications.
The Mac is easy to keep secure with under-the-hood technologies that require minimal IT management—providing crucial security while easing the burden of managing systems across the enterprise. With built-in features such as automatic software updates, application-based firewall, strong encryption tools, and integrated Internet security, systems are secure right out of the box. For easy customization, the Mac delivers robust tools that help IT administrators control system and server safety in just a matter of clicks.

sources:
http://www.apple.com/business/solutions/it/security.html