This Microsoft guy suggests that Microsoft Vista is so secure
it doesn't need antivirus software.
"I'll give you an example: My son, seven years old, runs Windows Vista,
and, honestly, he doesn't have an antivirus system on his machine. His machine
is locked down with parental controls, he can't download things unless it's
to the places that I've said that he could do, and I'm feeling totally confident
about that," he added. "That is quite a statement. I couldn't say
that in Windows XP SP2."