Okay so out of these three cards which is the fastest and i can get all three of these cards the same price so price aint a issues. And im not fussed about power consumption as i have a OCZ 600W thanks
As you can see above, they are all similar in performance. I'd suggest either the GTX275 or HD 4890 based on the age of technology and efficiency. Of those two, get whatever is cheapest or has the best warranty/brand.