The Flashback malware had a heyday on older Snow Leopard machines, and this article from April really puts things into perspective.
Not only is the old adage “Macs don’t get viruses” rubbish, but the days of buying a Mac and using it as-is until it dies is also over. Now, just like on the Windows side, I recommend waiting 3-6 months after a major release before considering the upgrade… but on the Mac side, it not just “should consider“, you should get the upgrade after the bugs get worked out. Your security depends on it (if recent history is anything to go by).
And, as always with negative Mac news, a disclaimer: I have many reasons to recommend certain Apple products to certain people, and this news doesn’t change that. I already knew Mac’s security was over-hyped. I can’t afford to be caught in the hype when clients depend on me to give them level-headed security advice.
*June 11, 2012 Update*
Many of you may have caught wind of OSX “10.8” aka “Mountain Lion”. Yes it is coming out soon, but no, that does not make going to Lion now a waste. Apple is accelerating their OS release schedule, so if you wait a few months after one release, you will undoubtedly hear rumors of the next release as you wait.