I've already tried some previous Betas of Microsoft's upcoming Service Pack 1 for Windows Vista on several PCs and while it (still) works fine on my Media Center, it had some trouble on my Notebook.
If you haven't heard about it so far, Windows Vista SP1 is an update to today's Windows Vista that, along with improvements delivered to users via other channels, addresses feedback from Microsoft customers. In addition to previously released updates, SP1 will contain changes focused on addressing specific reliability, performance and compatibility issues, supporting new types of hardware and adding support for several emerging standards. SP1 also continues to improve upon the IT administration experience. Unlike Windows XP's SP2, Windows Vista's SP1 is not intended to be a vehicle for releasing new features; however some existing components do gain slightly enhanced functionality in SP1.
While SP1 contains valuable updates to Windows, organizations don't need to wait to deploy and can experience the improved security, management and deployment benefits of Windows Vista today.
Currently, Microsoft is targeting a RTM release in Q1-08, depending on customer feedback and the quality of the beta. The SP1 RC was released to the 15k Beta Testers on Microsoft Connect and on Thursday, December 6, the RC was made available via MSDN and TechNet subscribers. Furthermore, Microsoft plans to release the SP1 RC bits to the public on TechNet anytime next week.
SP1 is going to be released in two waves. The initial release of SP1 will include 5 languages (English, French, Spanish, German, and Japanese). The second release containing all 36 basic languages will occur afterwards.