Jeff Jones has thrown up a report (available in PDF on his web page) on Windows Vista's 6 months security record and compared it to some competitors.

Like the 90 day results I posted up a while back, Windows Vista is still leading the field at this milestone too.

Windows Vista security vulnerabilities compared with other operating systems

Looks similar to the 90 day report, Windows Vista having just half the number of vulnerabilities as the supposedly "secure" Mac OS, somebody should really do them for false advertising.