I throw this into the discussion: “Music and the Power of Sound: the Influence of Interval and Tuning on Consciousness” by Alain Danielou.
If I understand this book correctly, Danielou states that the non-equal-tempered scales of India and China can have greater influence on consciousness than the Western equal-tempered tuning.
The first chapter of the book is very “new-agey” but then he gets down to the history of musical tunings in Europe, India and China.
He also says that part of the reason for our Western tuning was inaccurate transmission of musical knowledge from India to Greece several thousand years ago, resulting in the loss of critical pieces of information. The modes, for instance, are garbled remembrances of Indian tonal modes, with the knowkedge of the sustaining tone forgotten. At one point he mentions that our equal-tempered tuning had been independently discovered several timnes in China, but merely recorded and not used because it was too inaccurate in its emotional effect.
Arrgh. I don’t quite have the musical terminology for this…
Danielou also seems to imply that it may be possible to have a predictive science of the effects of music: in other words one could design a piece of music to have a very specific emotional effect on the listener.
It’s been a while since I read this book, and it was a bit beyond my simple knowledge of music. I think that my music teacher understood it, but I didn’t know enough to understand his version of it. So it remains in the “intriguing puzzle I will get back to” section.
But I highly recommend it to any musicologists out there. Maybe they can explain it to me… 
Afterthought: it seems to me that the greatest influence of Western popular music these days is through rhythm, not pitch or interval.
I gather from my drumming friends that the drumming in Western popular music is far simplified from its roots in Africa… I take this from an excellent essay by Michael Ventura, “Hear That Long Snake Moan”, about the African roots of American music. It was in the Whole Earth Review a while back, and also in one of his collections.