What is important to note with this second snapshot is that it breaks the X Server ABI for input, video, and extension interfaces. This means that users of X Server 1.8 that depend upon the binary NVIDIA and ATI/AMD graphics drivers will need to wait for an appropriate driver update that brings ABI compatibility with this new X Server. NVIDIA should be supporting the interface changes soon, while if based upon AMD's past actions, it will be some months before the Catalyst Linux driver delivers on X Server 1.8 support.
There are just under 150 changes in X Server 1.8 Snapshot 2 that touch the DIX, EXA, XQuartz, and other areas. The release announcement for X Server 1.8 snapshot 2 can be found on xorg-announce. X Server 1.8 under their new release process is planned for release at the end of March and is expected to have xorg.conf.d support, removal of HAL support, and other changes.