It's like the thief can break your padlock, come into your house, clean out your valuables, and shoot you. That's why we try not to keep so much valuables in the house. Even if the thief does come in, all he gets are trinkets. Of course, if you keep lots of valuables in the house, then you should install, an alarm system, CCTV, hire guards, etc.
My point is, don't get obsessed with computer security on your home PC. Get the usual anti-virus, firewall, and set the SSID on your wireless router, etc... None of these are truly secure, but we have to balance security with convenience and cost.
There are other ways to protect your valuables and information. Try not to keep valuable/secret information on your PC. Just burn it and keep it in a DVD-R. Keep 2 separate bank accounts (if you have some wealth). The one with a lot of money, you should minimise fund transfer or other high risk activities, especially to 3rd party accounts. Then keep another account with just enough money in it for transactional purpose, like GIRO, pay bills, online purchases, etc.
People are quite sensible about their physical valuables. All they need to do is to apply the same common sense online.