Many community members have expressed concerns over the visual experience of the Windows Basic theme, and, we heard you loud and clear. In fact, we too wanted something better, and we've overhauled this theme with an all new version. For those who haven't been following the discussion, let me brief you on the issue.
Windows Vista uses the Windows Display Driver Model (WDDM) to deliver some amazing user experience features collectively called Windows Aero which include; Desktop Composition, Glass window frames with colored glass, window thumbnails and Flip3D, a new window management facility. All of the Windows Aero features are enabled in Windows Home Premium, our Business SKUs, and Ultimate assuming you have the appropriate hardware. On Home Basic, you get Desktop Composition with opaque colored glass windows frames.
If you don't have a display driver capable of running WDDM you'll get the Windows Vista Basic theme which does not benefit from some of the more graphically intensive features such as desktop composition and glass window frames. This is a good, clean interface called the Basic or Standard theme, but lacking the glass window frames of Aero.
Screenshot: Differences between Aero Glass, Old Basic & News Basic
Screenshot: New Windows Vista Basic
View: Windows Vista Team Blog