BoF3's soundtrack is definitely one of my favorites, and the themes in the areas are usually spot on for those areas
and the final area has a theme (I think there is more than one, cause the "final area" is a huge place that has a few different parts to it) that is basically like a reflection or echo or foreshadowing to the final boss theme
which is just a tidbit that tickles me a lot
anyway, stopping there cause otherwise I will start to gush about every little thing and probably actually spoil stuff XD