Some "classic" game music

Zelda
R-Type
Secret of Mana

BF 1942

None of the MGS music is 'classic'. Now, THIS is classic.

Command and Conquer: Red Alert - OST https://www.youtube.com/watch?v=yGgnywWO6Ts (ALL TRACKS)
Total Annihilation - Soundtrack - https://www.youtube.com/watch?v=BxAdOQtAFEs
Dungeon Keeper Soundtrack - https://www.youtube.com/watch?v=O6iHgOEp0Fg
Cannon Fodder Intro and Recruitment Music - https://www.youtube.com/watch?v=Qc2fulUF64w (probably my old time favourite)

and i discovered Blur - Song 2 thx to fifa 98 or what number was it

https://youtu.be/JpO16qXT2KI

the whole top gear ost is unbeatable.

This particular PC Speaker version

Warlords Battlecry III (main theme)
(I hope it is "classic" game music :D)

Rock n Roll Racing
ToeJam & Earl: Panic on Funkotron
Comix Zone

To Zanarkand

Probably not exactly classic, but close: Rome Total War. It's one of my favourite soundtracks ever. It just fits the game perfectly...

Turrican 2 - The Great Bath
Diablo - Tristram Town
Doom II - Them Bones

Super Metroid have one of the best soundtracks

The greatest game ever created
evolution of a classic
it's just super

I like a lot of songs from the SNES Donkey Kong Country series. Brings back so much Nostalgia :)

DKC 1
DKC 2 (best out of the 3)
DKC 3

This one is from a friend of mine.

https://www.youtube.com/watch?v=CoGFV_xxR64

C64 music is best music ;)

Metroid fusion
I choose this one not because I like it somehow more than others but because it freaking made me crap my pants when I was a child and played Metroid waiting for some alien monster to pop out!

Tetris! :D