"the electro-jazz music puts me to sleep..." --- hmm. I find the current campaign music perfect but if there are really people like this, the team could go for something creepy/intriguing but has an electro beat that's still not disruptive enough.
I think part of what's going on is a generation thing - meaning some players grew up with the original X-COM/UFO and are adults now, while other players are kids who never played the original game because of their age and when it came out, and for one reason or another find UFO: AI on the net and try it out then review it.
Point being, you have more than one generation and age group playing the game, and different tastes, likes and dislikes for certain types of music. This brings me to my next point:
Destructavator is right though --- inserting a "track player" should solve subjective issues. I think it'll bloat the installer though. Or will it?
I didn't quite mean this, but you're close - what I meant was organizing the many soundtracks into groups based on genre, then having a game option for choosing which set to use for the game. Someone who likes gentle, atmospheric sounds could choose the "atmospheric" setting for the option in the main menu, and they would hear those types of tracks when they play. Some young kid who head-bangs to pounding progressive metal or something could choose a different setting in the main menu, and they would hear tracks from a different group when they play.
This proposal wouldn't add too much "bloat" to the game, not a lot of extra code-work really, depending on how it would be implemented, and we almost have enough tracks in the collection for grouping them in such a way, which, for your question:
Idea: Can we see a list of music tracks? Where are they kept? We can then make a poll of some sorts.
Yes, they are all OGG files, under "base" then "music" if you have an SVN copy, otherwise if you grabbed an installer and have PK3s, un-zip the "music" pk3 and you'll have all the current accepted tracks.
You can play OGGs with the open-source VLC media player, which does also come in a portable version if you don't want to install unfamiliar programs.