Vinnyh, I am a .Mac subscriber
Virex is a program one gets in the cost of the membership. I'll give you a contrast. I work on a Windows box. I update virus definitions daily. I run a spyware detection/deletion program every couple of days.
On the Mac, I update virus file definitions once a month. It has caught a couple of PC viruses attached to emails. They would not have harmed the Mac. It has never caught anything that would hurt the Mac. I have never had a virus on a Mac, and have owned them for over a decade.
Does not mean it won't happen, but it does not seem to be a danger at this time.