Mesa 7.9 was released in early October and over the past two months there's been a plethora of work going into this open-source graphics driver infrastructure, including Mesa core, the classic DRI drivers, and most interestingly with the new Gallium3D graphics driver architecture and its drivers and state trackers.
Mesa 7.10 should contain readied support for Intel's Sandy Bridge processors that will be released in Q1'2011, XvMC Gallium3D support in the R600g driver if all of the code is merged to master prior to the 7.10 branching, ATI R300 compiler optimizations, faster Intel driver performance, a multitude of 3D driver improvements to the Radeon HD 4000/5000 series, an improved LLVMpipe driver for faster CPU-based software rendering, possibly the Vega state tracker improvements, and much more.
The current release notes in Git also mention support for the following extensions: GL_ARB_explicit_attrib_location, GL_ARB_texture_rg, GL_EXT_separate_shader_objects, and GL_NV_primitive_restart. Though the support for these new extensions vary between the classic Mesa and Gallium3D drivers.
Mesa 7.9 was the point at which the default ATI R300 era graphics driver switched from being the classic Mesa driver to the newer Gallium3D-based solution, and while some have speculated Mesa 7.10 could already be the point at which the R600 Gallium3D driver becomes the default for all newer ATI Radeon graphics processors, it doesn't appear to be the case. Also not found in Mesa 7.10 is any form of Radeon HD 6000 series open-source support or VIA's unseen Gallium3D driver.
With Mesa 7.10 set to arrive in early January, it should make its way easily into Ubuntu 11.04, Fedora 15, and other H1'2011 Linux distribution updates. Mesa 7.9.1 will also be available for those just looking for bug-fixes atop a tested Mesa 7.9 stack, but of course we love the latest Mesa code due to all of the improvements across the board.
Ian's plans are outlined in this mailing list message.