Outlook Team blogged about design improvements in this new version of Outlook 2010.
When designing Outlook 2010, we worked hard to ensure that the colors, shapes, and text used within the product provide a pleasant experience and make it easy for you to get work done. We have done this by redesigning parts of the user interface to give Outlook a clean, crisp, high-quality look that is free from distracting visual elements. By simplifying many parts of the user interface, we've allowed your e-mail messages and meetings to shine in the foreground better than ever before! Let's take a look at some examples of how the new visuals improve Outlook.