Opps, my mistake, yes, it's suppose to replace the 767.
Maybe originally it was supposed to replace the 757, but the only model of it that is in the 787's capacity range is the 757-300. Boeing will have to address a replacement for the 757-200 eventually. Airlines like Continental have found it very useful for hub to point flights across the Atlantic. It would be nice if a 757-200 replacement could offer enough range to fly from interior cities in North America to Europe.