Just to throw in my .02....

I don't think any of this will accomplish anything except put McAfee out of business and put the hurt on Symantec. Regardless of what Microsoft's intentions are, no amount of AV scanners and firewalls will fix what is wrong with Windows.

The problem with Windows is not about viruses, worms, firewalls, or even bad code. It's about bad design choices. It's about having the entire OS installed on one monolithic C: drive instead of having a distributed file system where you can have /, /tmp, /usr, /var, and /home mounted on separate partitions with different execute permissions (noexec, nosuid, nodev, etc). It's about every user on the system needing Admin privileges to run basic applications because the directory layout was designed for a single-user environment (and not particularly good even for that). It's about things like this.

Again, it's about choices that were made many, many years ago before any of this was ever thought of up in Redmond, and about trying to create a patchwork to cover up those choices. You may patch one particular hole, but it will never be right. Nothing can fix Windows except a complete rewrite from the ground up, which will break the API and just about every application out there.

And we know how likely that is.