I wouldn't touch NAV. I've had such horrible luck with the Utilities and Sys Works...
Besides, they install kext files in your system, which I just don't like.
While articles say there are no known viruses out there for OS X, in a work place like mine where we have Win2K servers and XP boxen, a virus is a virus and can be passed on.
Anyone have a good recommendation for AV? What about Intego VirusBarrier?
Remember, just because it won't affect us doesn't mean we can't pass it on to others.