What is your favourite song in game?

Stormblood spoilers within my post, so hiding it away.

Favorite "theme": Answers.
Favorite "field theme": The Lochs, both daytime and nighttime.
Favorite "battle theme": Ala Mhigo.

If I had to pick one out of all of these here, to be honest, it'd be Ala Mhigo. The theme for that dungeon is just so good.

For me it's a tie between The Warrens (Snowcloak theme) and Mushroomery (Matoya's cave theme).