Warhammer 40,000: Armageddon Soundtrack:

Steam downloads game soundtracks to a separate folder in your game's Steamapps directory.
You can right-click on a game in your Steam Library, select Properties>Local Files and click Browse Local Files to access that game's directory.

The soundtrack itself consists of 12 tracks:

01. The Battle for Armageddon
02. Thakka's Plot
03. March of the Steel Legion
04. Dante's Retribution
05. Death Mire Falls
06. Yarrick's Choice
07. Crossing the Palidus Mountains
08. CUTSCENE Horst's Introduction
09. CUTSCENE Von Strab's Speech
10. CUTSCENE Faldrak's and the Space Marines
11. CUTSCENE Dante's Speech
12. CUTSCENE Yarrick's Finale