You need to use a checked list box control to control your navigation, instead of a datagridview on the left. Yes you lose the flexible databinding, and have to write the code manually, but that will look great.
Also please follow my instructions on this post to make your datagrid look continuous, and get rid of the ugly default lines. http://www.componentfactory.com/forums/viewtopic.php?f=3&t=1816
Also please remove the Outlook 2003 standard control colour name surrounding the text (Das Redesign geght voran),. Instead use a Krypton Panel and try and find a colour that matches Outlook.
Personally I am an Office 2007 purist and think the best Krypton Toolkit icons are http://www.glyfz.com/glyfz2007.htm
, and Component Factory as well, but for my present application, I need far more icons, but your application looks as if it could use them (CF that is). I just don't think that the Vista Type icons suit the Office 2007 Blue/Silver/Black themes, but they would suit the Sparkle themes.