First off, the 260.19.04 driver adds support for the nvcuvid API, which is a way for decoding video and exposing these surfaces to CUDA, which will allow applications to perform custom processing of the video like with trans-coding and video-processing applications. This NVIDIA API has already been available for Windows but now works with CUDA Linux platforms too.
Also on the video front are continued VDPAU bug-fixes, VDPAU now fully supports Xinerama, enhanced the VDPAU overlay-based presentation queue to allow it to be used in SLI setups and when the Composite extension is enabled.
For those more interested in NVIDIA's OpenGL support than video, the 260.19.04 driver provides full support for the OpenGL 4.1 specification with supported GPUs, better OpenGL Xinerama support, and adds in a lot of support for new OpenGL extensions. New OpenGL extensions added to the unofficial GLX protocol support include GL_EXT_texture_integer, GL_ARB_stencil_two_side, GL_EXT_transform_feedback2, GL_NV_transform_feedback2, and GL_NV_conditional_render. New GLX protocol support includes GL_NV_point_sprite, GL_EXT_stencil_two_side, GL_EXT_point_parameters, GL_ARB_transpose_matrix, GL_EXT_framebuffer_blit, and GL_EXT_framebuffer_multisample. The GL_EXT_geometry_shader4, GL_ARB_shader_objects, GL_ARB_vertex_shader, and GL_ARB_fragment_shader extensions have also been approved by the Khronos ARB as official extensions.
Other changes to be found in this NVIDIA Linux x86/x86_64 driver update include support for configuring individual displays as any eye in passive stereo mode when using TwinView or SLI Mosaic, ColorSpace and ColorRange features for HDMI, support for configuring the dithering mode when driving a flat panel on a modern NVIDIA GPU, support for SLI Mosaic, GPU processor clock reporting to the PowerMizer page of the NVIDIA Settings UI, and other bug-fixes. The header files for OpenGL, VDPAU, CUDA, and OpenCL are also no longer distributed with the binary NVIDIA driver going forward but they need to be acquired from separate upstream sources.
The official change-log and download links for the NVIDIA 260.19.04 Linux driver can be found at NvNews.net.