I could give a thousand answers to this question
@Beyond, but for time constraints (And likely due to forum restrictions), I shall present my five favourite Video Game OSTs.
Payday: The Heist - Code Silver (from the "No Mercy" heist):
Metal Gear Solid V: The Phantom Pain - A Phantom Pain:
Wolfenstein: The New Order - House of the Rising Sun:
DOOM - Message from Dr. Samuel Hayden/Title Drop:
Grand Theft Auto IV - Soviet Connection: