If u wanna good video card for multimedia then buy ATI, but for games u know what u have to buy 
well a store i worked in had a signed deal with Asus as official distributors, so Asus sent a guy to be with us for a week and teach us some of their work ways,anyways,during one coffe brake we asked what he thinks what is the best pc sys
reply: durring my work expirience i learned:
-work computer(video editing, cad, 3d design.....) Intel multy-core cpu and ATI grafic,
-gaming computer AMD cpu and good Nvidia grafic
reasons: working pc guy needs a multy cores to multy task(example one core renders video, one burnes dvd, one is for windows stuff and still has one to work confortably with),plus ati is more work oriented(just look at their site and how often they release hotfixes for games)
gaming pc need one strong cpu to push the game to max and a grafix that can run it smooth(Nvidia is more 3d, directx oriented)