IMO, Conficker and the newer breed of viruses are more insidious than the old kill your PC kind. In biology, those germs that are too effective at killing the host seldom survive. Those that can happily coexist without causing apparent adverse effects will proliferate much longer and infect many more hosts. It's the fact that there is the hive-mind aspect of the newer worms that is the most dangerous. All they have to do is wait dormant until x number of machines are infected, and then they could generate enough network traffic to cripple the internet or a select site of their choosing, with ransom demands included. How much would it be worth to say, Amazon.com to get their connection back? They'd be losing hundreds of thousands in revenue per hour.

The days of russian script kiddies are gone. Now it's the work of organized gangs of cyber-criminals.