Microsoft co-president Jim Allchin is confident enough in the security of their new operating system, Windows Vista, that he says it may not even require antivirus in certain situations. Vista features many new security features, including an improved firewall, an all-in-one security suite (Windows Defender), and other features such as Kernel PatchGuard.
Allchin talked about two new security components which give parents control over what their children can and cannot do on the OS. Parental Controls allows parents to monitor/manage their child's privileges, which include web restrictions, time limits, blocking games, blocking specific programs, and activity reports.
The second feature is Address Space [Layout] Randomization. It helps to fend off malicious attacks by rendering system kernel object code in memory.
Allchin says he is happy with the current security level of Vista. He said: "Windows Vista is something that will have issues in security, because the bar is being raised over time. But in my opinion, it is the most secure system that's available, and it's certainly the most secure system that we've shipped.
http://dailytech.com/article.aspx?newsid=4894What-No Avast- No Vista Then