Stella - Kashiwa Daisuke - very long, but very cool song, and the recommended songs by ASUNO after it plays are pretty good too, if you're into piano, especially Swan Song.
Dope Crunk - Beats Antique - I think most of their songs are pretty good, a lot of them have a similar feel to them.
Whatever this song is called - The band name is Wang Wen and they have a song called "Break the Cars" that's pretty good as well.
Breakdance of Yao - Shanghai Restoration Project
Light's Theme from Death Note soundtrack
So yeah, music sharing and discussion thread, gogo. ^^
Edit: Some more:
Plini + Sithu Aye - http://plini.bandcamp.com/album/i
http://plini.bandcamp.com/album/sweet-nothings









I played it myself last week. Lemme tell you, I don't watch anime, I don't read manga, and I had never read a visual novel before. Maybe never will again. A reddit thread came up in /r/gaming about KS, and I saw that it was made by 4channers and thought it might be a laugh. That fucking thing broke my heart. I'm serious, I was emotionally catatonic for hours afterwards and I'm a grown man. I don't know if those music vids from the soundtrack that Discreet are posting are really hitting anybody here, but having played the VN some of those tracks hit me like a freight train. 
