I have a HTPC running Windows 7 that has Microsoft Security Essentials installed (mostly to stop it from bugging me). My audio/video editing machine is a Mac wi

I have a HTPC running Windows 7 that has Microsoft Security Essentials installed (mostly to stop it from bugging me). My audio/video editing machine is a Mac without any antivirus software installed. And my development machine is running Ubuntu LTS without any antivirus. What's awkward is I don't even know which option to upvote.