The next laptop for the Ubuntu 12.04 power consumption investigation is the Lenovo ThinkPad T61 with the Intel Core 2 Duo T9300 "Penryn" processor and NVIDIA Quadro NVS 140M graphics.
Right away when idling, the ThinkPad T61 power consumption with Ubuntu 12.04 is lower than Ubuntu 11.10 by three Watts, which is significant for this aging but still useful x86_64 laptop. In fact, with Ubuntu 12.04 LTS it is finally at the power-levels of Ubuntu 8.04.4 LTS from four years ago. This notebook is doing better power-wise than previous releases due to a variety of small power optimizations during the Pangolin cycle.
Not only is the power consumption slightly lower when running OpenArena than on Ubuntu 11.10 (as aforementioned, the first release with the Nouveau Gallium3D driver by default) but the performance of this older NVIDIA Quadro was doing noticeably better with Nouveau from the Linux 3.2 kernel and Mesa 8.0.