In my opinion, as long as you dont mind SLI-ing, I'd go with another 670 (black friday is a good time to buy it). You'll get the best bang for your buck.
Good point. I got the first 670 last black Friday for $260, if I can get about the same I guess it is worth it. I just didn't want to pay $400 for another one if a 290X (like Geofelt suggested) is the same. Thanks for the reminder, I'll wait until BF and see.