There's a certain difficulty in producing music that can be played for upwards of 40 hours without a player getting annoyed with it. Patrick and Zach of Fat Bard have done a really good job in theming all the tunes in crashlands with the main theme (not here, YET!), and somehow managing to give them an appropriate spin for the biome-specific music.
The Bawg is creepy, the Savannah a bit jungly, and the Tundra nice and wintry sounding.
Let us know what you think, and which is your favorite. I'm extremely partial to the night music, myself.