Cuda wont matter for any of the VJ apps you use. Really. CUDA is just a driver add on for a programming language similar to OpenCL.
What you want is high number of cores, high vram and high bandwidth.
There are better cards than the one Brian sent, like the new NV 570/580 line, which has a shit ton of VRAM:
Read that. All that said, if you are building a Hackintosh, I really can’t be of much help if problems arise.