the main security issue at any computer is in front of the computer.
I started my it-history in 1981 on an Apple-II.....I owned an Atari 1040ST and I was proud to have a 20MB-Hardrive connected to it.
I was product manager at Commodore, and I launched the very first 386-Tower-PC in 1988, parallel to the Amiga-2000.
I never had any virus on my computer, but I'm really frustrated with pc's, or better to say Windows. The very first Windows version, which I start to like is "7". Never the less, I never ever would install a Windows PC without virus-protection.
On a mac it is a different story. But believe me, we also will see viruses for Macs in the near future, and you better be prepared.