Interesting to see that the 787 is heavier per seat by about a 100kg than the 767 it is supposed to be replacing. Guess all these weight saving technologies are eh.... really heavy.
Remember, it depends on the number of seats installed. Some Airbus 330-200s have 264 seats. Others have over 400, so the config has a LOT to do. This comparison will only be fair when a high density seating 767-300 is compared to a high density seating 787-800........