X Server: It's a toss-up at this point whether X.Org Server 1.9.x will be used or X.Org Server 1.10 will find its way into Ubuntu 11.04. The xorg-server 1.10 release is due out in mid-February, which concerns the Ubuntu developers, albeit the upstream X team has been releasing their servers on time as of late. So far there aren't any major features coming about in X.Org Server 1.10 (though RandR 1.4 should land), which means there's less of a reason to go with this release, but at the same time there should be less fall-out of switching to the latest release. If an X.Org Server 1.9 point release is used in Ubuntu 11.04, the Ubuntu input developers want the entire input layer from X.Org Server 1.10 back-ported into their 1.9 build so they can have the latest multi-touch work. There's also some desire to see input redirection support. It will be properly decided later whether to use 1.9.x or 1.10.
Mesa 7.10: The Ubuntu developers questioned whether to go with Mesa 7.10 or 7.9.1 for Ubuntu Natty. Fortunately, it sounds like their decision is to go with the Mesa 7.10. This is because Intel Sandy Bridge support should be complete by then so there will be a better Intel experience, which Canonical cares about. We're happy to see Mesa 7.10 as well considering all of the features it will boast over Mesa 7.9.x, which should have XvMC for ATI Gallium3D, among other changes.
ATI Gallium3D: At least the R300 Gallium3D driver will become the default in Ubuntu 11.04 for using this new graphics architecture on hardware up through the Radeon X1000 (R500) series. The R300g driver replaces the R300 classic Mesa driver as the default in the Mesa 7.9 release and Canonical will now switch over to this newer driver with Ubuntu 11.04 since it performs the same or better (based upon our tests), provides better OpenGL support, and the upstream developers are losing interest in the classic R300 driver. However, as the ATI Gallium3D driver requires KMS/DRI2, there was some talk about whether to still include the classic driver and also the DDX driver with user-space mode-setting support. It appears that they will at least still make ATI user-space mode-setting an option in Ubuntu 11.04 before dropping it in Ubuntu 11.10.
It wasn't brought up in the discussion whether to use the R600g Gallium3D driver over the classic R600 Mesa driver. The R600g driver is quickly catching up to the classic driver and carries support for the Radeon HD 2000/3000/4000/5000 generations of ATI GPUs, but chances are we won't see this Gallium3D driver become the default until at least Ubuntu 11.10.
Nouveau Gallium3D: While the Nouveau KMS driver has been used since Ubuntu 10.04 LTS for providing 2D support, the Gallium3D driver for offering up OpenGL support will not be going into Ubuntu 11.04 or any other release until the upstream Nouveau developers commit to providing support (or a "1.0" release). This is a bit of a pity considering Ubuntu's new desktop requires Compiz and Nouveau runs rather well here. Nouveau can run many games fine as well, albeit it's not as fast as NVIDIA's proprietary driver.
Linux 2.6.38 Kernel: It's believed that the Linux 2.6.38 kernel will be used by Ubuntu 11.04. While not brought up in the X discussion today, this is exciting as going with 2.6.38 would give hope that we may see some Radeon HD 6000 series open-source support for Natty. We likely won't see Northern Islands open-source 3D support in Ubuntu 11.04, but at least kernel mode-setting support would be good. We could also see Radeon page-flipping and possibly VIA's overdue code.