Well, money runs the world sunny is the proverb here i'm afraid
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As to any graphic card, there are a few aspects:
For example GPU Engine, Memory Specs, Feature Support, Display Support, Thermal and Power Specs. The important ones are:
the GPU, includes: Graphics Clock (MHz), Processor Clock (MHz), Texture Fill Rate
Memory specs include: Clock (MHz), Standard Config, Bandwidth
Feature Support: SLI, 3D, Physx, DirectX, OpenGL and shader pixel.
Of the three that you said the last one's the best and its the costliest as well. There are better still out there but they are costly. So you have to look at your budget. Still, the costliest, the best.
For most games these days, you'll need a card that is simply put 512MB or greater, DDR3, at 512 or greater Mhz frequency and capable of Pixel shader 4.0 and OpenGL. A card that has all these is automatically DirectX 10 compliant.
