I can’t say much about the latest AMD cards as I haven’t kept up that much but the 970 Is really great bang for the buck regardless of the 0.5GB slower memory. The step up from a 970 to 980 in performance is not big and the price difference is quite big. I’d say if you don’t plan on buying another one any time soon, go with 970 or 980 TI if you can afford it. If you plan on going with a better card when the exchange rate is lower, don’t buy anything until you do, buying a 960 now and upgrading to a 980 later would be a huge waste of money and you could have gotten a 980 TI for the same price instead. Depending on where you are I would guess it’s the extra applied tax (Usually about 25%) that you’re paying over the US price rather than an exchange rate difference (unless you’re buying from the US).
TL: DR
Buy 960 if that’s all you can afford any time soon.
Buy 970 if you want bang for the buck.
Buy 980 TI if you have the money to spend.
Don’t buy 960 now and upgrade just a bit later, that’s a huge waste of money.