Monster Hunter all their themes,

final fantasy 7 crisis core,

payday the heist,

Morrowind theme,

Red Orchestra 2/rising storm

The 仙剑奇侠传 series

1 original
1 remade
2
3
3.5 instrumental
3.5 vocal
4
5 instrumental
5 vocal
Also 5
What should have been and felt like the theme music for 5
5.5
Also 5.5
and

The 轩辕剑 series

2.5ish
3
3.5 synthesized
3.5 vocal rearranged
4
4.5
5's de facto
5.33
5.67
6

You are just asking, or really want to know?

Ok, here are my 20 favorite soundtracks.

Cheers!

Super Hexagon and Electronic Super Joy.

I love music from FTL. I don't usually listen to that kind of music, but there's something soothing and space-like in this soundtrack.
Besides that, I really like Final Fantasy series soundtracks by Nobuo Uematsu, especially the orchestral versions by his band The Black Mages. Bastion, Super Hexagon, HoMM3 and Borderlands 2 are also pretty great.

Unreal Tournament Super Meat Boy Payday 2

Unreal Tournament Super Meat Boy Payday 2

Rayman
Croc
Unreal Tournament
Mirror's Edge
Dust: An Elysian Tail

So many great soundtracks. Some:
Frozen Synapse
Capsized
Mirror's Edge
FTL
Unreal
Crusader: No Remorse(I miss mod-music in games)
Mechwarrior 2 (31st Century Combat / Ghost Bear's Legacy / Mercenaries)
...many more

Skyrim

PAYDAY 2

Akira Yamaoka - Silent Hill <3

Katamari Damacy

Trine 2 has an amazing soundtrack.

It may not me my favorite(I don't remember many soundtracks right now) but I love Mafia 2's soundtrack so much :D This is the reason I like to listen to old rock and roll and 40-50s in general :D

L.E.:I was actually refering to radio, not soundtrack XD

Purely to listen to just for it's music on it's own? Ace Attorney, especially the jazz arrangement releases. A good blue note scale with a bit of rain is just wonderful for me.

I'll use this opportunity to pimp one of my websites - RetroTracks.net
Just something I made ages ago back when I used to listen to old game soundtracks a lot.

Probably Shadow Of the Colossus; it's like Godspeed You Black Emperor, only 100% orchestral. Or at least I got that vibe from it. Other great runner-ups are Yamaoka's Silent Hill soundtracks, pretty much all of them. The guy must have been influenced by mid-90s Swans, and I'm kind of a fan of them, so it's understandable. I also love Jesper Kyd's score for the 4 "real" Hitman games, great blend of industrial and neoclassical. Then there's Carmageddon with its Fear Factory madness which never gets old, and since we mention licensed stuff, the Need For Speed series and Hotline: Miami are always a favourite.

Persona 3 and Persona 4

Super Robot Wars Alpha 3. Final Fantasy VIII; IX and X. Every Castlevania soundtrack. Skullgirls. There are games I've played just because of their soundtracks.

Glad I found this post so now I can say that I love the Merry Payday Christmas soundtrack from PAYDAY 2 that was released :) can't stop listening to it. My favorite song is "If it has to be Christmas".

Hotline Maimi My god so good ;-;

Final fantasy music is awesome. Especially the remakes by the The Black Mages band.
I also like Persona 3&4 music.

Alice: Madness Returns soundtrack. It's dark, twisted and beautiful music.