My Day is an entirely new app in Office 2008 that is really a control center for all the information you might want to see at a glance. Tasks and appointments can be created and updated here, and that info is updated in Entourage.
This is a new Excel template that lets mere mortals, like you or me, keep track of our finances without having to worry about creating formulas and the like.
This is indicative of the work MS is doing on Office 2008. The functionality here isn't new, but they are presenting features that are already present in the product in such a way as to make them useful to the user.
Taking some cues from Pages, Office 2008 for the Mac has a new layout called "Publishing Layout View." This is designed for all those folks who write newsletters, flyers, and brochures (do many people still do that?).
It is pretty slick, during the demo I got they highlighted the text overflow tools. Word keeps track of your text blocks, and will resize them on the fly.