Internet Explorer 8.0 and Data Execution Prevention (DEP/NX)
Eric Lawrence just posted some commentary about IE8 and DEP/NX. As you may know, IE7 supports DEP/NX, but it's disabled by default owing to compatibility issues. Well, DEP/NX is now enabled by default for IE8 when running on Windows Server 2008 and Window Vista SP1 and later :-)
If you build any form of extensibility mechanism for IE, you should read his post.