If you're thinking about trying out the Ubuntu 11.10 Beta release later in the week or are beginning to wonder about what the graphics driver options for Ubuntu 11.10 "Oneiric Ocelot" when released in October, here's a collection of information you'll want to know about the graphics drivers to be found in Ubuntu 11.10.
There's still more than a month until the release of Ubuntu 11.10 (it's planned for 13 October), but being past the feature freeze and the packages providing the graphics support are critical to the Linux desktop, they shouldn't change much between now and October.
The Linux 3.1 kernel isn't making it out for a few more weeks and just before the final release, so Canonical is playing it safe and sticking to the Linux 3.0 kernel although the still-in-development release does provide some nice improvements to the DRM graphics drivers and other areas of the kernel. Users can manually upgrade to the Linux 3.1 kernel and it should be relatively safe.
Over Mesa 7.10.2, which shipped in Ubuntu 11.04, the Mesa 7.11 release has many improvements. See the linked article for full details, but there's support for new OpenGL extensions, there's slowly more of OpenGL 3.0, more mature Intel Sandy Bridge support, initial Intel Ivy Bridge support, new AMD hardware support, GLSL compiler improvements, Gallium3D enhancements, better Nouveau driver support, and many bug-fixes. Ubuntu is not shipping Mesa with floating-point textures for obvious legal concerns.
Mesa 7.11 was released just a few weeks ago, but there are already many great improvements building up for Mesa 7.12/8.0. While Mesa Git master is usually in a reasonable state, those wishing to fetch this latest code that has Xorg state tracker improvements, a new R600g winsys back-end, the GLSL-To-TGSI translator, pipe-video, and other work, you will need to build it yourself. The other option is to be using the xorg-edgers PPA.
The xorg-server package in Ubuntu Oneiric has not received a major upgrade. X.Org Server 1.10 was also the release used in Ubuntu 11.04. There is now X.Org Server 1.11 that carries a lot of bug-fixes, and not much in the way of introducing major features, but it was decided early by Canonical they did not want to follow xorg-server 1.11. The 1.11 release does not merge some of the input work they have been tackling and they wanted to play it safer in case AMD (or NVIDIA) was slow again in supporting the ABI used by the new xorg-server release.