PowerPoint 2007 and 2010 represents a significant upgrade from PowerPoint 2003 in terms of ease of use and the availability of new and expanded tools, and it is impressive - you're going to love it. Microsoft is doing a great job of bringing presentation development tools and style capabilities to the mainstream user.
So will you still need PowerFrameworks? Most definitely, yes.
The bulk of the added diagrams in PowerPoint 2007 and 2010 are not offered through PowerFrameworks. And the bulk of PowerFrameworks is not offered with PowerPoint 2007 and 2010. A couple of diagrams that PowerPoint 2007 and 2010 have added seem redundant to what PowerFrameworks offers; but, in reality, they are not redundant at all. For example, the horizontal flows that will be available in the PowerPoint 2007 are structured very differently than those in the vast library offered through PowerFrameworks.
PowerFrameworks engineered and developed the many horizontal flow series to be interchangeable and so that each segment can contain the maximum amount of content. You will notice that the arrow points on the horizontal flows offered in PowerPoint 2007 and 2010 are much more elongated. This means that there is less usable area inside the arrow for content. Also, the very large library of horizontal flow variations offered by PowerFrameworks are not possible through the use of flow tools in 2007 and 2010 PowerPoint.