Imaginary scenario: The US, Russia, China, Europe, India, and all the private space companies in between combine resources for a sustained space exploration program beyond Earth. They can choose any location on Earth for their new program's launch site.
Question: Energy-wise, what is the most optimal location on Earth for launching rockets?
Would a launch pad on Mt. Chimborazo ( 1° 28′ 9″ S, 78° 49′ 3″ W), be the most efficient launch pad on Earth in terms of delta-V? Or does distance from the center of the Earth not contribute much to the energy required to launch a payload into space?
Note: I realize building a launch pad on a mountain and sending rockets up to the mountain isn't very efficient itself, but I'm just curious.