Virus free for over 15 years running Windows on multiple computers. No AV. Also no MS mail apps on personal systems. Yes to both router-based and client-based firewalls (in and out).
I'd argue that simply not using IE is more effective than AV software.
For the records, I am 15 years virus free on my Windows based machines without an antivirus, using IE daily since IE4 as my main browser, and using Outlook as a mail client for the last 10 years.
And, never seen any BSOD on Windows Server boxes since Windows NT4, in the last 10 years.
And, an uptime of more than 2 years on a Windows Server machine not connected to the internet and not needing any update-> reboot.
It's quite easy to disprove popular believes with single examples. Neither the former nor the latter are relevant, IMO, to prove anything, if not apparently support the arguments of this or that system's fan.
I am not saying that this is the case. I am instead saying that IMO the best way to protect oneself from viruses Is to keep ones machines as updated as possible, and yesterday's McAfee issues, statistically, does not change that. Of course, if such a disaster happened again one may decide do drop McAfee and opt for some other product.
Otherwise, as to my personal experiences above with IE, OL, AV Software, DSOD, Uptime, etc... I must have been extremely, extremely lucky so far.