This is a matter of personal taste.
If you are planning on getting a dot Mac account, then Virex comes free with it. Norton AV is also OK for the Mac but you have to pay for it separately and there is a yearly subscription to the AV Definitions. Of course, the Virex is not exactly free considering the dot Mac subscription fee. If you are planning of getting the firewall as well, then Norton is probably the way to go. Steer clear of SYSTEM WORKS, as it is no longer fully supported by Norton and is prone to finding strange problems with your machine which is claims to be able to fix but doesn't.
Bottom line. Norton for the AV and the Firewall, you really should have the firewall.
Hi. I'm planning to buy a 12'' inch iBook G4. I don't know what antivirus to buy, if Norton or Virex. Please give me your opinions and thanks.