ATI Has Open-Source Drivers Too
Since late last year the open-source Linux community has been ecstatic about the growing progress made by the Nouveau developers. Nouveau is an X.Org and FreeDesktop.org project for developing an open-source 2D/3D display driver for NVIDIA graphics cards. With NVIDIA Corporation not providing hardware specifications, this driver is being written through reverse-engineering NVIDIA's binary display driver. While the developers of Nouveau are making great strides and this driver is taking shape, the open-source ATI driver must not be forgotten.
For those that may be new to the Linux scene, ATI Technologies had released specifications to the Radeon R200 (8500 to 9200) series to X.Org developers quite a while ago. For those graphics cards, there is an excellent stable and open-source driver built into X.Org and since then ATI discontinued R200 support in their fglrx binary driver. However, support for the Radeon R300 series had to be reverse-engineered in order to construct a supportive driver (due to ATI not providing the needed specifications). The R300 driver now is nearly complete for desktop users wishing to play older games or simply benefit from Beryl and Compiz, but the driver is certainly not perfect. For instance, RS480 support with the R300 driver was only started recently and still has a way to go. Some of the other work left to tackle includes general optimizations, implementing the TTM memory manager, smooth/alpha shading, anisotropic filtering, and fixing a number of different bugs.