The most delicious game soundtracks you ever heard?

The musics composed by Jesper Kyd.

He made the musics from Hitman, Assassin's Creed, State of Decay, Warhammer Vermintide, etc.

Persona 5 definitely stole my heart with its OST

FEZ - Adventure by Diasasterpeace
The Old City Leviathan - Intro, Menu by Atrium Carceri

Gargoyle's Quest (Game Boy). Here's a medley cover on youtube.

Final Fantasy's.

NieR: Automata - For all the controversy of this game, it’s just amazing music

Commandos 2 and 3.

supergiants' games have awesome osts: Bastion and Transistor (those I played), but I'm pretty sure also Pyre and Hades are great too :D
also Prince of Persia (2008) and Mirror's Edge have really nice music

talking about composers, you can pretty much always bet on Jesper Kyd, Jeremy Soule, Micheal Giacchino (the ones that come to mind right now, I may add others later :D)

bastion soundtrack and metal gear solid 3 soundtrack are some of my favorites.

A few more,'cause why the hell not.

Harry Potter and the Philosopher's Stone
Warcraft I
Heroes Of Annihilated Empires
Empire Earth I & II (especially II)
Sea Dogs II

Gris has a beautiful soundtrack. The game is brilliant (96% positive on steam), and the amazing soundtrack takes it to a different level