You can actually change the color scheme for the default Microsoft Office 2007 suite. It comes with Blue color scheme by default but there are two more color schemes involved for enriching the UI experience.
The color scheme can be changed by clicking on the Round Office icon at top-left and then clicking on Options button at the bottom.
In the Personalize section of options, you can select Color Scheme from the drop-down.
The three Color Schemes include Windows XP (blue), Windows Vista (Gray) and (Black). Here is how Gray one looks like –