This article neatly sums-up the “MacDefender situation”: The best protection against malware and viruses is education and common sense, in that order. The better users are educated about what their computer does and how, the better they are able to identify scams.
The smartest thing computer-savvy people can do, is teach their less adept friends and family members how to deal with these kind of situations and set-up their computers in a way that reduces the risk of being infected. The latter should happen with an explanation of what changes are being made and why, because nobody wants to feel stupid.
