In addition, the Mesa Gallium3D implementation now supports g3dvl, which was the Google Summer of Code project this year to create a unified video decoder that isn't bound to specific GPUs but sits atop Gallium3D and uses the graphics processor's shaders. Back in September we shared the state of Gallium3D video decoding.
Users interested in checking out the latest 3D code can acquire the mesa/gallium-0.2 git branch. As Stephane noted in his mailing list message, "that does not mean nouveau magically became stable overnight, but at least we don't have multiple trees all around." Nouveau's 3D side is still being actively developed and certain NVIDIA GPU series are currently working better than others.
The mailing list message announcing this branch merger can be read on dri-devel.