There is a silver bullet - but it is aimed at the users:)

As Drakino pointed out, a lot of it comes from the way users of MS Windows have not been educated - yes, computing has been brought to the masses, but there has been little sign of the teaching of sensible practices.

If home users are going to run windows PCs, they should at a minimum install straight from XP Service Pack 2, not install XP then download the SP, as they are likely to be compromised before they get it.

They should have a hardware firewall as well as a good software firewall (not XP's own thing - bleh)

They should create an admin account at startup, and leave it well alone - using only user level accounts for everything.

Jeez - there is a wee list of technical things that can help, but really - it is mostly a user education problem...which means it will never be fixed.