After your motherboard, the graphics card is the most important part of your Hackintosh. However, Mac OS X wasn't designed to support a wide variety of graphics cards, so it's not always clear which graphics card is the best choice. To answer this question once and for all, we've put together this guide on choosing the right card for your own Hackintosh.
Mac OS X Mountain Lion will add support for NVIDIA's GTX 600 series and AMD's Radeon 6900 series of graphics cards. However, if you want support right now, it is now possible to enable full resolution and graphics acceleration for the NVIDIA GTX 670 in Mac OS X Lion, by following alfa's method.