Good Soundtracks? I'm game.
Deemo: a casual game based around music. Many different tracks and styles.
Listen: http://deemo.wikia.com/wiki/Songs_by_Collection (there's a page for each song, with a youtube link for each too)
Download: https://www.dropbox.com/sh/qdzxn3menwuk5he/AAAL2v6303lMlAf1ma54tJjga?dl=0 (not complete, not all of it's available)
Cave Story: a small indie game that had a bit of attention for a while. Largely chiptune-y with a variety of tones. The remastered is better in my opinion.
(the following links are ordered by the original soundtrack then the remastered)
, https://www.youtube.com/playlist?list=PLD57659BEA5C0015BDownload: http://www.cavestory.org/download/music.php , http://www.mediafire.com/download/fu3fiww0x872d7r/Cave+Story+3D+OST.7z
Mother 1-3: a classic old RPG series I'm sure you're familiar with.
(the following links are given in order by game)
Download: http://starmen.net/mother1/music/ , http://starmen.net/mother2/music/ , http://starmen.net/mother3/music/
QBQBQB: a cute puzzle game. Few tracks but they feel very well made.
Listen and Download: http://rezoner.bandcamp.com/album/qbqbqb
The World Ends With You: a fast-paced combat game on the DS. A heavy emphasis on musical score.
Download: itunes does have it, but you can google if you prefer to avoid apple's DRM.
Steins; Gate: a visual novel game about time travel. The soundtrack's mainly accompaniment, except for some great moments of drama (Gate of Steiner's a personal favorite)
Download: itunes again.