I agree on the 770. However more future proof (if anything like that can be said regarding hardware) is the 4 GB version. At least a 3 GB vRAM should be in place in any GPU to date. I currently play Wolfstein new order at Full HD and it uses 2.7 GB of vRAM. For most games and if you won't play Full HD 2 GB will suffice but as long as new games are coming out the 2 GB will become standard and start pushing further. I speak for experience when I bout my 560 TI 1 GB a few years back in BF3 Full HD had some problems...
The AMD 280x or 290 with 3GB/4GB might be a good purchase in matters of price/performance. Just consider the price of each model, since a 770 with 4 GB will cost a bit more. However currently NVIDIA gives a free copy of watch dogs, dont know what bundle games AMD is currently offering.
Whatever you choose make sure you search reviews for the GPU you are buying BEFORE buying it.