It's a real problem, especially for home users. Blaster caused over $2 billion dollars of damage last month. Remember that Parson kid they picked up in Minnesota? When they found him, he owned about 6,000 boxes. That's a lot of machines. Also, it took down a DMV office, I think in Maryland. Many smaller businesses were affected as well.
Microsoft's code is so buggy, that it doesn't surprise me that your friends are making big dollars in this field. As far as the viruses go, you saw the story that was posted a few days ago about the kid who was using machines affected by trojans, as ftp servers. They use them to DDoS other machines, store their tools and games, and other activities that leech off your bandwidth. Most of the time you don't even know they are there. That is the problem. These script kiddies with too much time on their hands, are releasing all kinds of destructive code and it is a pain to clean up.
I spend a great deal of my time counseling people on fixing their computers and cleaning up these messes, when it could have all been prevented with a few basic pieces of software and hardware. At home, I run Linux, OS X and Windows. I am always attacking my own machines, to make sure they are secure. Not everyone can do this, so I try to inform as many people as possible when this stuff becomes available.
You've been quiet this weekend, any fun stories to share?