June 2017 - last edited June 2017
There are many great soundtracks like Witcher and ME series, but I'm gonna go with something a bit older
MechWarrior 2 In-Game Soundtrack - 11 - "Pyre Light"
https://www.youtube.com/watch?v=gX4G1RJYTi8&index=11&list=PL3E409CD81FFF6F55
This was back in 1995 when fully orchestrated soundtracks were relative rare (on PC in particular), so this one blew our minds. Game too. So moody with it's heart-beat drum lines, epic horn and string sections mixed with modern "synth" sounds.
The entire playlist.