[ocre]

Katamari Damacy. Lonely Rolling Star.

Always makes me smile.

[ectogemia]

Angel Flavors Present from Katamari gives me chills most of the time. The Earthbound soundtrack -- not to mention the game in general -- is extremely uplifting. Insert Rupee's Great Job remix always does the trick, too.

Gotta second Calum's suggestions, too, especially any of the Animal Crossing soundtracks. The melodies have that nice nostalgic quality to them.

[Garpocalypse]

Ragnarok online:

http://www.youtube.com/watch?v=bnccYItJsCM

Perfect World:

http://www.youtube.com/watch?v=S4Lyx7aWsZI
http://www.youtube.com/watch?v=-5xjq...feature=relmfu

and everything from Skies of Arcadia.

Actually Tomb Raider Underworld had some great stuff too

http://www.youtube.com/watch?v=YrQtr...eature=related

[Gollgagh]

Legend of Mana

Doom

at the same time

[Dissidia]

FF7-10
Nostalgia like no other.

[ectogemia]

Yarrrrr, forgot a few. Ape Escape has an amazing sort of ephemeral liquid dnb soundtrack. The Mammoth Cave track reminds me of DKC music but better. You heard me.

Braid's soundtrack is amazing for relaxation and thinkin' time. It's a really warm strings-based Celtic-inspired sort of thing, lots of nice fiddle work and such. Hell of a game, too. The story is quite evocative.

Anamanaguchi will make anyone instantly happy, although I guess their stuff apart from the Scott Pilgrim soundtrack isn't technically VGM, but it might as well be. On that note, Disasterpeace's VGM soundtracks are all excellent and generally pretty uplifting or pensive. He even made a procedural music generation game that pumps out some fantastic melodic ambience and is very relaxing to play.

[Annie Felis]

The Chrono Cross soundtrack is very cathartic. Something about Mitsuda's music is relaxing.

I also like to listen to World of Warcraft music (specifically pre-Cataclysm stuff), because I loved the hell out of that game's music.

[AngelCityOutlaw]

Street Fighter and/or Castlevania soundtracks.

[Evilhead]

For me it's the Minecraft soundtrack, extending to C418's work in general. Looking at my playlist it seems I've listened to the entire album at least 50 times. I put it on while I'm translating. It helps me concentrate for some reason and relaxes me as well. Usually I can't concentrate on other things, especially writing, when I am listening to music but it's different with this soundtrack. And I ended up falling in love with the soundtrack long before I ever played the game itself. It's just great music to have on. Listening to it right now in fact.

[JH Sounds]

Every track in Echochrome.