Ubuntu wants to be a great gaming platform and as part of that audio and graphics support are two of several areas that need to be improved.
Ubuntu's ultimate goal in terms of the graphics (OpenGL) support coverage is that there's a consistent experience between Linux and Windows / Mac OS X. Aside from Valve collaborating with NVIDIA and AMD to improve their closed-source Linux graphics drivers (along with Intel on their open-source graphics driver), at this UDS Copenhagen discussion was Valve possibly launching Jockey / Ubuntu Software Center directly when needed for prompting users to install the binary graphics drivers when needed for a game instead of using the slower, less-featureful, and buggy open-source graphics drivers.
What Ubuntu developers are looking to push to game developers as the recommended API Is using OpenGL 2.x and OpenGL ES 2.0 where the functionality is the same, which would mean the broadest possible hardware coverage across different devices. The closed-source NVIDIA / AMD graphics drivers meanwhile support OpenGL 4.x while the open-source Mesa/Gallium3D drivers are around OpenGL 3.0~3.1 for the most part.
Briefly talked about was how to handle the full-screen window mess for X11. Of the possibilities discussed here for Ubuntu was creating a resolution manager for ensuring the temporary resolution change is handled accordingly, do GPU scaling rather than changing the mode, or extending the window manager hint that was proposed recently by Ryan Gordon.
When it comes to the audio support for gaming on Ubuntu, they're generally in much better shape than on the graphics side. There's a near feature parity with audio support to Windows, but there are some patents relating to surround sound that might prove troubling to Linux users, there isn't much hardware support for offloading effects to sound cards under Linux, and PulseAudio latency issues might be problematic. JACK was talked about as having lower-latency than PulseAudio, but then users would lose Bluetooth audio support and other features. The numbers tossed out for audio latency were 5ms on Ubuntu when using raw ALSA or 25ms when pumping the audio through PulseAudio.