They might drive down the price a bit, but all current indications are that they won't beat the 5970.
For Nvidia's sake, I would hope that isn't the case. If they release their DX11 cards six months later and don't perform better, they better go for the budget market as ATI just won full share of the highend. I've been personally waiting to see the cost & performance of the GTX 470 to see if worth the upgrade. I may have to make the switch to ATI at that point