I would probably get the 5850 or 5870 if I got a 5000 series card, I guess I'm just getting impatient (4890 has 256 bit instead of 128 too).
I just don't want to get a dx10(.1) card and have dx11 become dominant in the next year. But the price and performance of a 4890 (especially over clocked, 285 competition?) seems pretty good to me now. Think I'm confusing myself.