[SonicVanguard]

For anything video related (photo and/or video editing) I always suggest going with ATI. Their RGB-CYMK and CYMK-RGB conversion is next to flawless. The only cards from nVidia that are close are their workstation cards (Quadro series). And then ATI cards still out shine nVidia - even a consumer level card from ATI will give you better, truer color than a nVidia workstation card.

I'd look at some of the high end HD cards from ATI or their FireGL workstation cards.

Now if money is truly no object, take a look at the 3DLabs Realizm cards. Those are just nasty (in a good way).

And before everyone jumps on the nVidia bandwagon - let me say this. Every video professional I know (and I know plenty) use ATI cards in their editing. Same holds true for photographers. And it's all because of color.