A question was asked why UA and AA didn't buy any 764's, I wonder why any airline would buy 764's over 772's. Don't get me wrong, I love the 767 series. The 2-3-2 seating is in my opinion the best seating arrangement.
But DL, for exampe, has 763's and 772's, so why the 764? Seems to me to make more sense to buy the somewhat larger, newer ground-up designed, longer range and not that much more expensive 777.