I like most of the music in Civ4, with two exceptions. One is the christian choral, but that's only one track, and I think I'll eventually replace it with something else. It simply sounds too wailing for me, but I know that many people like it.
The other exception is the whole modern era. I wouldn't mind if Adams' music were only boring, because then I could simply ignore it. Unfortunately it's annoying as well, so I usually turn it off. I think I'll replace the modern era music with the respective Civ3 tunes, which were *much*, much better (especially the jazz piece).