Service Pack 2 for Windows Server 2008 and Windows Vista

Service Pack 2 (SP2) for Windows Server 2008 and Windows Vista is an update to Windows Vista and Windows Server 2008. It provides customer and partner feedback-driven fixes into a single service pack, minimizing deployment and testing complexity. In addition to all previously released updates since SP1, SP2supports new types of hardware, and adds support for several emerging standards.

http://technet.microsoft.com/en-us/windows/dd262148.aspx