I also like a really large range of music compared to most people, and I've found that the better my ears have gotten, the more different types of music I enjoy. I think it's a combination of natural inclination/interest, and overall mindset. most of the time when I listen to music that's all I'm doing, whereas most people listen to music as a background to something else. my theory is this is because most people are highly visual creatures, but that is perhaps too far off topic.
fwiw I think a lot of it is cultural/social. very interesting experiment at columbia:
http://blog.pmarca.com/2007/06/paper-of-the-we.html
relevant part:
...Fortunately, the explosive growth of the Internet has made it possible to study human activity in a controlled manner for thousands or even millions of people at the same time. Recently, my collaborators, Matthew Salganik and Peter Dodds, and I conducted just such a Web-based experiment. In our study, published last year in Science, more than 14,000 participants registered at our Web site, Music Lab (
www.musiclab.columbia.edu), and were asked to listen to, rate and, if they chose, download songs by bands they had never heard of. Some of the participants saw only the names of the songs and bands, while others also saw how many times the songs had been downloaded by previous participants. This second group — in what we called the “social influence” condition — was further split into eight parallel “worlds” such that participants could see the prior downloads of people only in their own world. We didn’t manipulate any of these rankings — all the artists in all the worlds started out identically, with zero downloads — but because the different worlds were kept separate, they subsequently evolved independently of one another.
This setup let us test the possibility of prediction in two very direct ways. First, if people know what they like regardless of what they think other people like, the most successful songs should draw about the same amount of the total market share in both the independent and social-influence conditions — that is, hits shouldn’t be any bigger just because the people downloading them know what other people downloaded. And second, the very same songs — the “best” ones — should become hits in all social-influence worlds.