Putting aside all Japanese mistakes, the topic here is Touhou music! And when it comes to Touhou music, it's all about the doujin circles.
IOSYS, Sound Holic, Silver Forest, Sync Art's, Alice's Emotion, C-Clays, Maikaze, the list goes on forever.
A good place to find the best of the music is some of the "tours" that users put on NicoNico, which use the auto-jump feature to string together a long playlist of videos that combine Touhou fanart with the doujin music, creating an immersive Touhou experience. The most famous (or popular at least, with the most hits) of these is the スキマツアー (sukima tour / "gap" tour, a reference to Yukari Yagumo's power to create "gaps" between borders), which can be found here (registration required).
Some of my favorite songs: