Two good CAS-related blog posts:
Code Access Security is, in my opinion, an underrated .NET feature. I don't know if it is the firewall fallacy or that developers have just become used to developing with admin privileges (ha! fooled you with that link!). I have tried, in a security-conscious way, to move my web applications to a semi-trusted security model. Since I use SQL Server and a separate dll for data, it's not too bad. But I realize that users of other databases have more issues, and certain requirements dictate less stringent security needs.
As a side note (or maybe I'm just late to the party), but finally there is an OPML file for GotDotNet blogs.