Personally... I HOPE microsoft ruins computer gaming... on windows.
This could be the begining to the end of windows (probably not

)
But I can See MacOSX being the next "gamers" OS... just because its unix based, and it is the most "stable" os for regular computer users ( I dont mean stable as in never crash etc. but i mean like windows, you can count on OSX to "work" and be there.. with linux there are too many distros to keep track..)
But really... we dont have much of a choice right now, we are almost forced to use windows... and eventally forced to use Vista.