I think the large Asian cities are much more serious than those here in the USA. Tokyo, Hong Kong, and Singapore have murderer's rows of high end store and people who take music very seriously. My wife, who is from China, has several friends involved in the manufacture and distribution of high end audio equipment, who regularly call her, asking her to become their face in the US. From the feel I get, the high end is exploding in mainland China, and in a very mainstream way.
Special honors also goes to London. When you look at any of the English audio rags, it's apparent how much more in the forefront audio is than for us.
On the US side, Denver kind of seems to be at the fore these days. The traditional US epicenter, of course, has always been Boston, but the sun there is definitely setting.
