7. Some kind of direct video support (games, etc...). That's up to the Operating System, not to a desktop environment. And those solutions are available, it's called OpenGL and SDL, too bad only good game developers dare to use portable, industry standards instead of closed API's they don't even have full support for (take a look at the UT engine, Doom engine, Cube engine).

Sadly, OpenGL drivers on Linux aren't up to speed feature-wise. ATI's drivers are especially poor. For instance, you can't reliably create a buffer object on Linux without a fallback to the much slower PBuffer system.

Feature for feature, OpenGL 2.0 on Windows is sort of competing with DX9 and somewhat DX10, but on Linux you can't use any of the features required for a modern game engine. In order to ship a competitive title in 2007 you need multiple render targets, Shader model 3.0 support and floating-point buffers. UT and Doom are ancient games as far as rendering technology goes.