I would rather go for an AMD card when it came to multi-monitor setups. I don't know why, but it's a matter of personal preference , I guess.
Plus, I think it'd be easier with the AMD series.
Of course with a 2 monitor setup I don't think you're going to go into playing FPS games or the car ones, most probably for extended desktop space and work environment change. So for that you wouldn't need a very high end GPU, lower end GPUs will do the job too just need to make sure you have ample GDDR that's all.