I can only agree, the soundtrack is phenomenal. I hope that the complete soundtrack will be available, I would definitely buy it.
But I really can't decide on a favourite. One moment that was particularly epic to me was the "darker" reprise (don't know if this is the correct musical term) of "Down by the river" playing during the nautiloid crash cinematic, just before our character is flung out of the ship.
The Harpy Song really is enchanting, and I can understand every character failing their saving throw and just standing on the beach entranced.
"I want to live" is at the same time beautifully melancholic, peaceful and tender.
The fight themes are simply epic.
And one of my favourite scenes so far is helping Alfira to complete "The Weeping Dawn".
I love this game already. Beautiful music, graphics and perfect voice acting/performance capture, well written and interesting characters, and a story that - to me- promises to be epic.