well, personally, and usually, i'll reccommend you the AMD 6730 card, however, since both card are actually head to head each other, and you have the money, why not the nvidia 540?

since nvidia did pay developers to use their CUDA cores in games, why not?

if the graph is right, even my "really old" HD4670 can OC to get 3DMark06 8277 points, from peanut 6k++ points.... so why not the newer 6730 (that have much2 larger OC headroom) cant be OC'ed like nuts?

yup, you read it right, ATI cards runs much more cooler now. Thanks to nvidia's engineer magic. They forgot the heat and power issue and just concentrate on performance.

I love ATI really, but now games developer always use nvidia. I dunno why. Did nvidia pay them?

I forgot where, but I've read even Video encoding using CUDA yield worst results. Even Intel GMA can produce much2 better video Encode than CUDA. ATI using openCL produce OK results, but ultimately CPU encoding produce best quality encodes.