If you've written code to work with Outlook before, you'll have met the Object Model Guard's messages about a program trying to access Outlook. This change was a real pain for developers when it was first introduced. Since then we've all made our way around it by writing extended MAPI code or using things like Redemption or Outlook Security Manager. However, I was reading some info on the code security changes in Office 2007 and came accross this:

Security in Outlook 2007 takes advantage of the status of antivirus software installed on a computer. This change represents a major departure from the way the Object Model Guard worked in the past. If Outlook is able to detect that antivirus software is running with an acceptable status, Outlook disables security warnings for the user. This allows external applications that previously had to resort to Extended MAPI or third-party libraries to avoid security prompts under the appropriate conditions. This new behavior helps keep Outlook secure without overwhelming the user with excessive warning messages.

That is some awesome news IMO.