As a computer security professional I just have to chuckle about all the Mac user claims of security. The fact is there is not one single computer anywhere this isn’t vulnerable to exploitation. One of the main reasons there is so much focus on Microsoft products is the fact that they are so prevalent. If someone is in the business of exploiting machines, the best platform to concentrate on is obviously MS products just because of the shear numbers. If the numbers were reversed, I’m sure that Macs would be victimized just as easily. If any of you Mac users think you are invincible, you obviously haven’t seen the number of exploits available to hackers\malicious software for the Mac platform.
I believe you are correct. Macs make up something like 4.5% market share of all computers in the USA so most hackers aren't going to bother hacking them. The more prevelent they become (if) the more hackers will turn to them. Right now, there just aren't enough out there for the hackers to bother with the effort.
I agree with you regarding the overwhelming availability of MS vs Mac for targeting. Sure it’s more difficult to attack Macs, but not impossible. One day a very good hacker is going to write some scripts and tools for use against the Mac, and when it happens there will be much wailing and gnashing of teeth by all those Mac users who didn’t practice ANY kind of computer security because they felt safe.
No matter the platform, OS, or other security provided by your network, ALWAYS distrust unknown/unverified information be it an email or a website or anything else.