Reduced vulnerability? Just learn how to operate a computer. I did that years ago. I've run without spyware/virus protection forever, and never get anything. Just to keep things in check, I will install anti-virus/spyware software once every couple months to do a quick check, and I've turned out clean for years.
Then don't get a Mac (assuming you don't need the other software I alluded to). But there are many, many people who will not or can not learn "how to operate" a computer.
Though given how many issues there are with Windows boxes, it's fair to say the issue is not simply a matter of user incompetence.