Can't post links yet but:
Silent Hill series
Portal 2 (and Portal 1, but prefer the sequel)
The Binding of Isaac
Thomas Was Alone
Saya no Uta
And I enjoy some of the ones from the Sonic franchise too.

^ I love the Silent Hill soundtrack. It's what inspired me to take up piano. Second game had the best soundtrack in my opinion.

While the second is my fav I actually very slightly prefer the third's one. Though my fav song is still Betrayal.

The Silent Hill OSTs are fantastic. 2's OST is my favorite (and is tied with Majora's Mask's OST as my favorite soundtrack in general), though 4's pretty close IMO.

Every Tony Hawk video game

Both of these games are fantastic and the soundtracks are indeed fantastic.

Honestly, it has to be either DOOM, DOOM II or Ocarina of Time. I'm leaning toward OoT because of...

^ This is one of the most awesome things I've ever heard.
Also the Gerudo Valley/Fortress/Haunted Wasteland music is just classic. There's no way around it that it is just beautifully arranged.

This is a tough one for me. But it is a compilation of a handful of games.

Metal Gear Solid games, my favorite game series on the planet...
Final Fantasy 7, just love that music!
Chrono Trigger, nostalgic!
Zelda, pretty much any of the games
Child of Light, just go buy it and play it, you'll fall in love with the art style, characters, music...

I think I have more, but the names elude me.

Ha ha, I knew as soon as I saw your name that you were going to post the forest temple.

How do you feel about, The Arbiter's Grounds?