Greatest Video Game Music

Elder Scrolls III, IV and V
The Witcher 1, 2 and 3 (especially 3)
and of course: To The Moon

Oh, and how could I have forgotten Life is Strange?

edit: There's also Tales from the Borderlands

From the 16-bit era, Chrono Trigger and Final Fantasy VI can't be beaten as far as I'm concerned.

World of Warcraft vanilla music, "nostalgy" soundtrack for me.

Beautiful music

Terraria

https://www.youtube.com/watch?v=7dJrsmt9BOY

Edit:

https://www.youtube.com/watch?v=NFUOvBVoEB0

Also:

https://www.youtube.com/watch?v=Jm932Sqwf5E

Everything: http://store.steampowered.com/app/619940/Everything_OST/

there are only two really great soundtracks i will remember forever.
total annihilation
world of goo

Quake

Undertale, but I suppose y'all have heard that one said before.

From NES, I'd say Star Tropics and Star Tropics II. Have to agree with scuazmooq for SNES. Chrono Cross and Katamari Damacy are great for Playstation. The original Pokemon Red and Blue have special places in my hearts, too (Rocket HIdeout and Viridian City especially). Metroid Prime and Okami also come to mind.

If I had to said something lesser known, though, I'd probably say how amazing Myst's soundtrack is.

Aquaria :)

Recently I fell in love with all of Blue Revolver's OST.

Also obligatory: Transistor

Civilization 6
Dawn of War 3
Medal of Honor: Warfighter
MSG 5
No Man's Sky
XCOM 2

I'll try to timestamp my favourite pieces but I urge those who like instrumental music to listen to all of them with their full duration because they are really really good and the way the music picks up is so worth it to listen to.

That being said Warcraft spam incoming.

Anduin's Theme (I'm extremely obsessed with this one)
Lion's Rest (My 2nd obsession)
Two parts from Warlords of Draenor soundtrack
Nightsong (This generally makes me cry or tears me up because of the cutscene it plays in)
Vrykul

Diablo Tristram

Witcher 3 Ladies of the Wood (My ringtone :D)

The very new (published 4 days ago) and awesome Pyre soundtrack.
Also a bit older, but nearly as great Ori and the Blind Forest OST.

Grandia

My top 3 favourite themes atm.

KH BBS(Aqua theme)
https://www.youtube.com/watch?v=pfjEKGKz_zg&list=PLa_xhHBQ-8UVuzS8Zv5vXXSqkJHAZWaLo&index=6

Also roxas battle theme(similar like his normal theme)
https://www.youtube.com/watch?v=wHRL-JfXhFQ

Both taken from my playlist(you are free to explore for more music, its general music, not only themes XD)

Furi(My only chance) - My favourite one
https://www.youtube.com/watch?v=SeAAi7jWOl8&list=PLa_xhHBQ-8UVuzS8Zv5vXXSqkJHAZWaLo&index=4

What do you think of those themes? :D

chrono cross time's scar
https://www.youtube.com/watch?v=J46RY4PU8a8

Hotline Miami
Hotline Miami 2: Wrong Number
Grid 2
Life is Stange
Grim Fandango
Could add so many ;_;

No-one mentioned it, but Saints Row 4 had a great selection of music tracks. All the music the game had worked amazingly great in the game.

Since no one has said it yet, Ocarina of Time https://www.youtube.com/watch?v=ZzwvItK3JPI

Trine
VVVVVV
Bastion, that too
RollerCoaster Tycoon
Roller-Derby Disco Dodgeball
Assassin's Creed (II)
Payday/Payday 2 (couldn't pick just one say I grabbed a random one)
Super Hexagon
Cave Story+, also that
To The Moon

And that's all for now... :P

Half-Life 2

Yay, this topic again. Gives me another opportunity to link my usual suspects again. So....

Hell March 1,2 & 3 from the C&C Red Alert series.

There's also the Gradius V version of Aircraft Carrier which turns a notorious earworm into an epic boss theme.

From the same composer, there's the entire Ikaruga soundtrack.

And speaking of earworms, there's always Katamari on the rocks