I have not talked about Windows Vista/Server 2008 Service Pack 2 since October 2008. Today, Microsoft released it to the public for download. With Service Pack 2, Vista is just now ready to ship. By Service Pack 4, Vista will be fine. Service Pack 2 contains all the updates released since Service Pack 1 and adds some new features as well.
Windows Service Pack Clean-up tool (compcln.exe): Delete files from Vista RTM and SP1 that have been updated with SP2 versions to save space on your disk.
NOTE: Once you do this, you cannot uninstall Vista SP2.
Windows Search 4.0: Previously a free download for Vista SP1 is included in Vista SP2 and performs better.
Blu-Ray disc writing: You can now record data to a blu-ray disc.
Windows Media Center:Improved performance of protective TV Content in Media Center.
Bluetooth 2.1 Support: Vista SP2 includes support for Bluetooth 2.1.
VIA 64-bit support: Windows Vista now supports 64-bit VIA microprocessors.
Power management improvements: The default power management policies are approximately 10 percent more efficient than before.
RSS Feed gadget improvements: The Feed Headlines gadget for Windows Sidebar has been updated for better responsiveness and performance.
General improvements to the OS, compatibly, performance and reliability.
Sidebar Gadgets: Sidebar gadgets now take 100MB less RAM.
NOTE: You must have Service Pack 1 installed first before installing Service Pack 2.
You can download SP2 as a standalone installer or by Windows Update.