What is the best gpu currently available for Ethereum mining?
What do you mean by "best"? Simply the single GPU with the greatest possible hashrate? (What about dual-GPU cards?) The one with the best price:performance ratio? The best power:performance ratio?
Most of us would have some combination of those factors, and perhaps some more idiosyncrasies.
Sorry, it is a pretty open-ended question. I was referring to graphics card, rather than just the gpu - whether its dual-gpu or not. And by best, I would refer to both efficiency and pure performance.