SharePoint SP2 is Release to World (RTW) as of today.  Some of the highlights from the SharePoint team blog:

Benefits

Customers can be benefited from the following enhancements with Service Pack 2.

  • Performance and Availability Improvements

Service Pack 2 includes many fixes and enhancements designed to improve performance, availability, and stability in your server farms, including:

    • New Timer job automatically rebuilds content database index to improve database performance.
    • When a content database is marked as read-only, the user interface will be modified so users cannot perform tasks that require writing to the database.
    • Performance enhancement across nearly all the components.
  • Improved Interoperability

Service Pack 2 continues to improve SharePoint interoperability with other products and platforms.

    • Broader support of browsers
      Internet Explorer 8 is added into Level 1 browser support.
      FireFox 2.0/3.0 is added into Level 2 browser support.
    • Provide improved client integration user experience with Form Based Authentication. Now the client application can store user credentials instead of asking for them every time. For more technical details please refer to the updated articles on TechNet.
      Configure forms-based authentication (Office SharePoint Server
      http://technet.microsoft.com/en-us/library/cc262201.aspx
      Configure forms-based authentication (Windows SharePoint Services)
      http://technet.microsoft.com/en-us/library/cc288043.aspx
  • Getting Ready for SharePoint Server 2010

A new preupgradecheck operation is added to stsadm tool. It can be used to scan your server farm to establish whether it is ready for upgrade to SharePoint Products and Technologies "14". It identifies issues that could present obstacles to the upgrade process. It checks for several SharePoint Products and Technologies "14" system requirements, including the presence of Microsoft® Windows Server® 2008 and a 64-bit hardware, and provides feedback and best practice recommendations for your current environment, together with information on how to resolve any issues that the tool discovers. 

I am particularly excited about the early release of the preupgradecheck tool.  This will allow IT departments to begin planning 2010 deployment rollout well in advance, and identify any significant hurdles.  Of course, “performance enhancement across nearly all the components” is also a welcomed improvement!