Who knows?
But, a new card will not sell unless it is much stronger than anything available today, and that card will be very expensive.
Otherwise, the new card has to beat the current price/performance level. That will not happen until the mfg tech goes smaller than 28nm, down to 20nm. Most likely, you will see 10% better price performance in the value cards.
My take is to buy what you need today.
When your needs/wants change, sell it and replace with the next best thing.
If your budget is $700 for 2 GTX670 cards plus a 750w psu and a sli capable motherboard, OK.
If you will be using only a single monitor, consider buying only one GTX670 or GTX680.
You will game very well with that.
Save the rest for when you really need more.