Bungie’s Halo soundtracks are terrific, and I find myself agreeing with a lot of the responses here. A few I would mention would be the soundtracks to the Batman: Arkham series by Nick Arundel and Christopher Drake.
In particular, I love some of the tracks for Arkham City, the main theme is epic and certainly sets the tone, but some of the atmospheric tracks used in free roam are perfect for ambience. The tracks “Refusal Will Not be Tolerated” and “I Know What You Guys Are Thinking” have this amazing mysterious feel that fits remarkably well with traversal through the decaying streets of Old Gotham.
Arkham Origins has a very cinematic soundtrack, with heavy brass and percussion and it fits terrifically well during the many boss battles scattered throughout the game.