Microsoft will release Windows 7 SP1 to non-MSDN and TechNet subscribers starting February 22, 2011. The update will be available through Windows Updates for existing Windows 7 customers.
SP1 only contains two major new features, which will not affect the majority of users. The first of the two is RemoteFX, a standalone product that requires Windows Server 2008 R2 to be used. RemoteFX allows users to watch high-quality video and interact with 3D applications over a remote desktop session -- this will change the way Virtual Machines are used, as they have had limited display capabilities until now.
The second feature is an update for HyperV in Windows Server 2008 R2 called "Dynamic Memory". The feature is as simple as it sounds -- it dynamically allocates memory to virtual machines as required and is able to remove memory from virtual machines when others need higher resources.
Windows Server Team Blog