Whats the big deal about comparing the 5850 and 5870 against any gtx200 series? The 200 series was meant to combat the 4000 series of ATI not the 5000. Thats what the 300 series is for.
I'm not taking anything away from ATI here, those are some good results. But it's not a correct comparison.
I think one of the most important things to look at is the price to performance levels, yet again, which is where ATI seems to shine. The 5870 results I've seen, which, while far from concrete, show the 5870 beating the GTX295 in pretty much every benchmark test, while maintaining a price tag significantly lower. When you've got a card more powerful than the most powerful (current) opposition card for less cash, why would you go with the more expensive alternative? Not to mention, nVidia's top end card is pretty much guaranteed to cost at least $500 when it releases, if not more, and if the rumours are to be held even remotely accurate, then they won't even be a significant upgrade from the 200 series.