On the heels of last week’s post about the latest Java vulnerability, I came across an article over the weekend by Rich Mogull, TidBITS.com’s security editor. Here is the first paragraph of his article, followed by a link to the entire story:

“It has been over four years since I wrote “Should Mac Users Run Antivirus Software?” (18 March 2008). Although much has changed since then, my recommendations mostly haven’t. While Macs aren’t immune to malicious software (malware), and we even experienced one reasonably widespread incident in 2012, malware on Macs is still not nearly common enough to recommend antivirus software for everyone. And while antivirus tools are effective against certain known attacks, they often don’t provide the level of protection people expect.” [Emphasis mine]

Read the entire article here.
His bottom line opinion (in bold above) is exactly what I’ve been saying for years. Even though there have been more frequent threats identified as affecting Macs in recent months, I still think they’re rare enough (as well as being relatively benign in their threat levels) that the downsides of running A/V software on your Mac full time aren’t warranted.
There are a few instances where I might feel differently, one of which was mentioned in the comments appended to the above article. The example given was one where a particular user frequently uses flash drives to share files between Macs and PCs. In that case, running A/V software would be a good way to stop the potential spread of PC viruses via the flash drives.
If you still want to run a Mac A/V package of some sort, Sophos has a decent free option, and Intego’s products are also well-regarded.
Happy (and healthy) surfing!