My Vote for Best Outlook AddIn
Combines your Task list and your Calendar (something MS should have done a long time ago <clearing throat>. It is really smart at scheduling your tasks, even tho you have to run a command-line utility to get it to build your calendar.
It doesn't have support for Office 2003 yet (due to a bug in the OB2 Technical Refresh), but their Version 2 will support it in a few months. I can't wait.