Sadly, it's a shame that people put much faith in AV programs given their effectiveness (http://arstechnica.com/security/2014/05/antivurus-pioneer-symantec-declares-av-dead-and-doomed-to-failure/). I think author R.R. Martin has it right (https://www.youtube.com/watch?v=X5REM-3nWHg), keep separate machine for different purposes - one for serious work and one for messing around with. It doesn't feel like a good idea to use one machine for everything.
Symantec is mixing up stuff here to try to position themselves for the new hot profitable APT market. For one; the context of this quote about AV being dead was a WSJ interview with the CEO where he said it in the context if Symantec being able to increase their profit, as AV has become quite cheap and APT is getting all the nice profit margin - it was not said in a context of user need, but in a context of Symantec profit need.
Then they mix up some statistics about targeted advanced hacker attacks (APT), which of course isn't stopped by AV, but it doesn't make the treat from traditional malware any less. All reports and research show that regardless of APT, the threat from standard malware is increasing, not decreasing (just as those hit by Cryptolocker..).
Yes, AV is not 100%. There will be APT type attack that bypass it, and there will be time periods with brand new malware that bypass it. But that last point is often overblown. Well over 90% of actual real world infections are from known malware that would be stopped by a good AV program. Even a condom isn't 100% safe, that doesn't mean that it is meaningless to use a condom.