Future proof is a misnomer. There is no such thing. A card will be a certain speed, X. Your graphical requirements require a certain speed, Y. As long as X is greater than Y your card is sufficient.
There is no card that will make the gap between X and Y reduce more slowly. However, the more powerful the card you buy the larger the gap between X and Y is, thus the longer it will take to exhaust the gap.
This is a very fancy way of saying that if you want a card to be the most future proof, buy the fastest card you can afford to buy right now. If you are willing to switch cards more frequently then buy the best bang for the buck card right now, then sell it and rebuy the best bang for the buck card in the next generation.
The advice you take depends on your budget:
@$400-450: R9 290 or GTX 780
@$300-350: GTX 770 or R9 280x
@$200-250: GTX 760 or R7 270x (280 or HD 7950 is preferable if you can find any in this price range)
1) i agree with your analogy, but you are coming off from the assumption that Y is constantly moving forward, and since X is static i will always need to by the next better card so X is farther ahead from Y, however i think that all games in the next few years (6 years or so?) will try and fit the new consoles so Y will addvance a lot slower sooner than later. just like how system requirements in the past 4 years havent changed very much if at all. crysis 2 and AC4 has roughtly the same requirements. this is why my 6870 1GB can run most games on almost MAX for the past 4 years or so. since Y has stopped moving until the new consoles came out.
my point is - i dont necessarily need the best card possible since i dont think Y is going to move that far ahead. what i wanted to know is if there is a card that is likely to keep me gaming the the way i am playing right now (at that res with these demands from gaphics) that i will remain ahead of Y when Y slows down yet not buy the most expensive GPU avialable.
also, is there a reason most ppl advised on AMD and not Nvidia?
another important question that somehow ppl missed:
2) i have a 650W PSU. what PSU will i need if i upgrade to a 280X or 290 or 770?
3) is there a point in the near future where new hardware is supposed to come out that will cause a price drop?
how long should i wait before a new purchase without "over waiting" during a stagnant time period in prices?
and if there is such a new GPU that should come out that you know of - whose is it- AMD or Nvidia?
right now im probably gonna wait until june to see how watch dogs performs on my 6870... i just wonder how long i best wait after june....