Businesses and individuals take a hit on productivity because of security holes in Microsoft and other vendors software.
Lack of computer security: virus and worms effect on productivity
Obviously, no "outward facing" software (HTTP, SMTP, POP, SSH, etc. services) should be written in programming languages that do not effectively trap runtime errors (like buffer overflows).
The trouble is "fixing" existing systems. There is no shortage of viable programming languages with proper runtime error handling support: Java, C#, Python, Smalltalk, Lisp, Scheme, etc.
What would be the performance hit of running network services written in Python or C#? Considering the hit on lost human productivity due to insecure sfotware, who cares?
This is more of a concern for me than the average computer user: I get about 500 web sites linking to my site every month and about 3000 human visitors to my site a month.
I get about 100 emails a month from people I did not know before - I always answer every email that I get (non-SPAM that is), so I would imagine that I am in more than a few people's email address books. That is the problem! I have been trapping about 400 incoming virus containing emails a day for the last several days.
Still, the benefits of communication with people from all over the world far out weighs the 10 minutes a day that I have to spend on dealing with SPAM and viruses.