We all know NVIDIA is holding back. If the HD 4870 X2 will in fact be that good, It won’t be long until NVIDIA will crush ATI once again. But yes, 280GTX is the most powerful single core card on the market. From what I seen so far the “old” 9800GX2 beats the 280GTX, not by far tho. The bad side about GX2 it generates a lot of heat! Has 2 cores instead one 1 and its hug!. So ya 280GTX in my eyes is the best card on the market out right now.
Although I understand what you are saying about the GTX 280 being the faster single GPU card available, I don't see any reason to buy it when the HD 4870 provides 85%-90% of the performance for $300, compared to the GTX 280's $500 price tag.
Also when Nvidia released a 576mm2, 1400 millon transistor chip, I really don't think they were holding back.
And after Nvidia just blamed TSMC for their problems when they were not to blame, I think we can be sure who will be getting the first wafers off of their new 40nm production line...
So, I think we know who really opened the famous "can of whoop ass". Intel must be ROFL ATM.