I've had a single virus on a windows machine, and I was about 90% sure that it was going to be a virus and wanted to see what happened.

I don't run anti-virus software, but I think it's only the power users that are capable of doing so. User education is still too low. Would you trust your parents or grand-parents to "not install a virus" ?

Considering the kinds of vulnerabilities we've seen, this may prove difficult. I remember one where browsing to a folder with a specially crafted image provoked a buffer overflow that got exploited.