I'm posting this here just for those that havent heard about it. Whilst most current users won't really notice a change, if you game on your vista pc, this is a good update to be aware of with the impending DX11 cards and games.
Basically, DX11 libraries that are included in Windows 7 have been released as an update for Windows 7 and Window Server 2008. These initially were included in an DirectX SDK August Update.
KB971512 is the 'Windows Graphics, Imaging and XPS' Update and was released on 26 October 2009 and available from MS >
Make sure you have the latest (August) DirectX redistributable
installed and Service Pack 2 to ensure you have the complete set of libraries (including some tweaked backward compatibility support)
KB971512 is actually part of a group of platform updates that bring Windows7 resources to Vista, which you can read about and get download links from HERE
Im pretty sure that if you installed the previously linked August redist/SDK update that you actually wont need the october update > when I tried to install it said I already have it
Best try it and find out. (This kb is just under 5MBs)