Windows Vista 90-day Vulnerability Report
Just look at the chart below.
Funny though, I keep hearing of the unbreakable nature of the other OSs listed on the chart.
In this report here, Jeff Jones, a director in the security group at Microsoft, lists reported and corrected vulns for six (6) operating systems at the 90-day window.
The results seem surprising, until you see the chart.
Then it blows you away, revealing that there must be some truth to the current belief that the ubiquity of Windows makes it a prime target for malware and breaches and not the other way around.
Jeff is also allowing a download of his full report.