Terrible lack of real security improvement
The isolation of "apps" is good (one step closer to Linux security), but I get the feeling that it's gonna be just like Win 7: everything wants to mess with stuff outside the allowed areas and I have to click a message that comes up.
Secure boot goes about things in a way that leaves alternative OSes to rely on Microsoft, or removing a security layer (you can't get more FUD than making your average computer user have to decide to disable security they didn't know about).
The rest of this is IE10 stuff. While IE is integrated into Windows, we can use alternatives and IE can be used on previous Windows versions. Its security shouldn't be counted among Windows 8 improvements.
Also, Avast! Antivirus already has that popularity/safety rating thing as a plugin, tho it does it for the site. It's not a revolutionary feature.
