"How much" graphics card for P-shop CS 6, LR 4, for Nikon D3 user with RAW files?

I'm planning my next build (i7-3930, lots of RAM, maybe an SSD, all housed in a Corsair 800D case which I already use with my current build. My question is: what graphics card specs (other than 1 GB of VRAM) are important for me, so I don't underspend or overspend here? Which models from either nVidia or ATI are recommended?

I've been to the Adobe site and read all the articles about support graphics cards, etc. But aside from a recommended 1 GB of VRAM, I can't seem to find any articles or posts that provide practical advice on other specs and how to relate them to specific needs.

My Nikon D3 produces RAW files which run about 25-30 GB, uncompressed (14 bit depth), and I don't plan to upgrade to anything newer for last least the next 4 years. I like to work with uncompressed TIFFs and layers.

TIA.

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LongTimeNikonUser