I don't think the music is that bad, but it gets old after hearing it a few times.
The hard solution is to create your own MP3 files and use them to replace the ones in Civ3.
The easy solution is just to play your own music from another source, such as a CD player. I have two CD ROM drives on my PC and play movie soundtracks on one drive with the Civ3 disk in the other.
