At the moment its the hype and because ATI beat Nvidia to the punch there charging a higher premium than they would normally do, hopefully Nvidia comes and actually tries to be competing in price then we will be seeing price drops.
I expect to see the 5870 to be dropping to around 200-250 dont see it ever dropping below 200 for a while when Nvidia starts releasing there DX11 cards if they ever do.
They're charging probably around £30 over at the moment if that, big deal. I won't go out on the lash this weekend then, infact I'm not anyway as I'll be too busy with my card