Funny, this was on Slashdot yesterday:
Flight 4590 Didn't Kill the Concorde; Costs Did - Slashdot

"If the plane were around today — which some still fantasize about — it'd be like powering a stretch Hummer with dolphin blood. The airlines couldn't sell enough tickets on the small plane to even make up for the amount of fuel it needed to guzzle on its journeys, let alone cover maintenance for the technological marvel. (A Concorde's taxi to the end of a runway used as much fuel as a 737's flight from London to Amsterdam.) Customers were fine with ordinary travel times for a fraction of the airfare and the plane only took transatlantic journeys, because going over land was too disturbing. Too much noise."
It is a shame that nothing better and more efficient has come along yet, atmosphere bouncing spaceplanes are still far off, scramjets still melt from friction and supercavitation has not been sorted for planes yet.