Earlier today, we released the first version of the TFS Power Tools for TFS 2008!
I want to highlight the build notification application. This tool alerts you when a build is started or completed. If the build breaks, you'll know immediately.
I posted a preview of the build notification app back in September. Based on feedback, we have fixed bugs (e.g., it now properly handles the user logging out or shutting down on Vista) and made improvements (e.g., you can now disable servers in the options dialog that you don't want). See the preview post for more screenshots and details on how it works.
See Brian's post for the full details on all of the featues on this release, which include support for destroying work items and work item type definitions.