Currently any serious gamer has to use Cedega to use most windows games, what would be the effect with the slightly new version of windows, and DX10. On the flip side, Vista might be a flop and more developers might start developing for such platforms as Linux, but thats kind of a pipe dream
The growing userbase of Linux and OS X will continue to boost OpenGL popularity, so you will continue to see games with both DirectX and OpenGL rendering capabilites. Also, Transgaming will continue to emulate many DX features in OpenGL, which will not suddenly stop when DX 10 hits mainstream.
