The minimum I would recommend is the HD 4670 for any type of gaming. It is good enough for most games if modest graphics and resolution settings are used.
The HD 4350 is good enough to watch video.
just shut up i play assassins creed all maxed out on the same card and it is also known to play GTA IV all maxed out on a lower PC than Mine. and by the way my pc specs are
ATi HD 4350 512 dedicated,1200 shared
640 Gb HDD
3Gb DDR3 Ram
Vista Home premium.
It's all about your processor. you rgraphics card is only 40 % of graphics output AND AN HD4350 IS AS GOOD AS AN NVIDIA 9000 series +