Nope, not a single proper virus or even any lousy malware popping up in the last year or so. It has to be noted, though, that the attack vectors seem to have changed a bit.
AV software keeps picking up (sometimes nasty) stuff on private and business removal storage devices, most probably because people have no clue and no shame, sticking them into any computer available. It's like running around naked having intercourse with random people - not the smartest idea.
All machines have AV software installed, at home we run pretty much all of them. They all work, to some extent, some behave a bit like malware themselves, though. My least favourite has been named and shamed already in this thread.
Being 'careful' does not protect you from the more devious forms of internet threats, though. They rely mainly on exploits that require little to no user interaction.
Maybe your - always up-to-date and current - browser is keeping you protected or you don't run any extensions (flash/java/...), but it's pretty silly to run an internet-connected computer without antivirus software and/or a firewall. Generally speaking, people should be fined for doing so, as in most cases, they end up spreading nasties 24/7. And, no, it doesn't matter much if it's Windows or OSX these days, sorry. Haven't seen any bad stuff on Linux, though, but Linux is still more of a pastime of mine and doesn't get the bills paid.
One of the very low level fun bits of a firewall is checking on what program generates traffic. I was amazed to see Apple software wanting to call home every two seconds or so, easily for weeks and months without pausing once. So we run Apple's services but manually these days, life's just too short to put up with such nonsense.
