This isn't exactly relate to pop music per se, but I thought it would be nice to appreciate Japanese composers. There are a wide range of talented composers writing for all aspects of media: movies, classical, game and anime. Unfortunately they are relatively unknown compared to Western greats such as Hans Zimmer.
My favourite composer has to be Joe Hisaishi. As you may know already he's well-known for composing the soundtracks of Ghibli films. His songs are emotive: sometimes they're soft and relaxing, and other times they're haunting. There's a "Hisaishi" touch on all his scores that I love.
Summer (from Kikujiro no Natsu)
Princess Mononoke Theme
Asia Dream Song
I love those songs too, Asa Hisashi's a great composer indeed.
As a Final Fantasy fan, I must say I love Uematsu Nobuo! My favourite of his is "To Zanarkand" from FFX. I think the soundtrack is always a big thing about FF games. Uematsu is very skilled in composing music that fits the beautifully rendered scenery in the game, and draws out the emotion of that part of the game's storyline. I think I actually cried listening to this song (To Zanarkand) while playing the game... ^^;;
Speaking of Uematsu Nobuo, his pieces are really popular and somehow you really feel the story's mood in FF games through his music.
Two songs that I like best from him are memory of lightwaves and breezy.
Toshio Masuda's composition for Naruto are really cool for anime songs.
Two of my favorites are the Raising Fighting Spirit and Strong & Strike. Japanese drums are pretty distinct on the beat of those two music which I love best.
For some contemporary ones, my favorite composers/musicians are Yuhki Kuramoto and Norihiro Tsuru. The following are my favorites from them... (although almost all of their pieces are really good for me)
Romance - Yuhki Kuramoto (piano version)
Nostalgia - Yuhki Kuramoto
Piano Jewel - Yuhki Kuramoto
Last Carnival - Norihiro Tsuru
Moonlit Dancer - Norihiro Tsuru
Wada Kaoru is another composer I like who has created the OSTs for many popular anime series. The most notable songs he has composed come from Inuyasha:
To the End of Feelings
Half-Demon Inuyasha ← Personal favorite.
Evil, Demon Naraku
As a bonus, here's Road's theme song. I imagine a carnival with bloodthirsty clowns. Eek!
Talking about composers, I think everyone knows about Kajiura Yuki, the composer behind some popular series. She is mostly known for her works for games (Xenosaga II, Xenosaga III, Blood) and anime (.Hack, Mai-Otome, Pandora Hearts, Tsubasa Chronicle, Puella Magi Madoka Magica). Sometimes she would rearrange some of her songs, giving an entirely new atmosphere. The basic arrangements are awesome and touch you with deep feelings. That's why I like her. <3 She would sometimes compose independently, make groups (Kalafina and FictionJunction), and make concerts as well.
[Tsubasa Chronicle] Kajiura Yuki - believe
[Tsubasa Chronicle] Kajiura Yuki - rainbow
[Pandora Hearts] Kajiura Yuki - will
[.Hack] Kajiura Yuki - Grandfather's Violin