Depends how much you want to bang your buck. Obviously the fastest card is GTX 680, followed very closely by GTX 760 Ti (basically GTX 670 rebadged) and GTX 760 is the slowest one with the least stream processor count.

Better buy GTX 680, why? GTX 760 Ti is fast, but because its available to OEM only it uses crappy noisy and not very efficient cooler. You can fetch a good one at Garage Sales.

If u decide to go for GTX680 can pm me when u decide to upgrade maybe we can both benefit :3. i want let go my 680 n go for 970/980.

+ my warranty still up till 2016 

Oh man, so tempted to sell my newly purchased 760 for the 970.

Since the 960 has been delayed, I wonder if this is the best time to sell it.

Prices for 2nd hand 680/770 dropped to RM700 range and 290 to RM850 range in SG. 280x can now be purchased for as low as RM500 with 1 year warranty left in SG.