I'll start off with Raiden II's Repeated Tragedy.
A local restaurant had this game, and every time we went, I'd beg my parents for money so that I could play it. I wasn't very good at the game, so I never got past the first stage, and so I heard this song a lot. Really gives me nostalgia.
Also got to shout out Streets, from Timesplitters too. I put a lot of time into this game as a kid, and this song is what got me into futurepop (love me some VNV Nation).
FTL: Faster Than Light
MechWarrior 2
Total Annihilation
Hotline Miami
FTL soundtrack is great
A friend of mine plays video games on speakers and has the Hotline Miami soundtrack playing in the background of all games, so whenever he mics in, I hear that playing in the background