Masashi Hamauzu carries FFXIII on his back. Absolute juggernaut of an OST.
This track in particular, I just love the changes and then the vocals about 2 mins in. Orchestra with NIN 'The Fragile' style electronica (at least to me). So damn good and unique.
This one gives me an Avalanche vibe. Something about the orchestra on this OST, just recorded so well, great clarity and really powerful sounding.