--- Protect yourself, buy a Mac! ----
You are joking right?
Intel processors are no more susceptible to computer viruses than Motorola.
One could argue that Microsoft is more vulnerable, but that is only because it has a ton more users, and thus, potential victims.
The problem is not the processor or op-sys, its the evil hackers. They should be shot.
The old "more users thus more attacks" canard is easily demonstrated to be false, since the Apache web server (which runs on Unix systems) has much more market share and runs on many more machines; yet MSFT's IIS web server is far and away compromised more often.
It is an architectual problem - XP and Office are not well designed, while Unix and Mac OSX are. The better design makes it easier to verify where security holes might be, and then fix them.