Yes, you really do need a virus checker
It is starting to look like the Flashback virus has woken up Apple fanboys and they are starting to think that they do need to buy anti-virus software. Fanboys have always believed they were invulnerable to viruses because Steve Jobs told them his product was superior. They also tended to get arsy when people suggested that they were not important enough for anyone to want to hack.
But after half a million Macs were hacked by the Flashback virus so quickly it was fairly clear that their faith based security system had no clothes. Now antivirus vendors have been quick to seize the opportunity to bring Mac users into the fold. Flashback has shown that even those fanboys who do upgrade when they are told can't rely on Apple to save them. The whole problem, was caused by Apple refusing to update Java at the beginning of the year.
F-Secure, Kaspersky, Symantec, Avast and Bitdefender rushed out free Flashback detection and removal tools which proved more useful than anything that Jobs' Mob could come up with. These free Flashback tools are particularly useful for owners of older Macs who haven't upgraded to newer versions of Mac OS. Apple has told those customers who keep running their old flavours of software that they should have queue outside the Apple store with the others when Snow Leopard came out and it can't be bothered helping them.
Meanwhile, enterprise security vendor Sophos offers free Mac antivirus software for home users, competing against free offerings such as ClamXav and AVG's LinkScanner.