Yay, total music otaku here. :D
I like to think I'm on top of current Japanese music trends (at least I used to), but I have heard of only one of these. Anime music really is another world.
^ This.
Lately I've really started to like Tohoshinki, Arashi, MiChi and Kimaguren, the first two are pop boybands who I think actually do some really decent music, and Kimaguren is an easy listening duo who does what they call "beach music", so they're always great to listen to and MiChi is a really fun mix of pop and rock that's great to listen to.
I've always been a fan of rock, so flumpool (god I love flumpool, if you haven't listened to them, go do it, now) HIGH and MIGHTY COLOR, The Back Horn, FAKE, Tourbillon, Fujifabric, and Dragon Ash in their early days have been great music for me in that genre. Oh. Also, anything with Tak Matsumoto on the guitar is going to be really awesome as long as it doesn't involve Koshi Inaba on vocals because...gah. And when they aren't being totally generic (Hakanaku mo Towa no Kanashi for example), UVERworld is a great band.
I love J-Urban music as well, just not stuff like...Koda Kumi, can't stand her. mflo, anything with VERBAL in it, I'll probably like. I
really love listening to Ryohei Yamamoto's music as well as Rip Slyme, BENNIE K, Shonan no Kaze.
I really love the Nakta produced groups as well, they're all the same genre of music, more or less, but they really do show off that dance/techno side of music in a wonderful manner that is so easy to get lost in. I especially love Capsule's older stuff and the newer Perfume. Also a huge fan of anything produced by JIN, GReeeeN, BACK ON, and 2BACKKA, they're really great to listen to, I love anything that uses the keyboard and vocoder effectively.
Slightly older artists I love are Mr. Children, THE ALFEE, Fukuyama Masaharu, V6, Do as Infinity, DA PUMP, BONNIE PINK, Porno Graffitti, and Kinki Kids.
Generally can't stand any form of Visual Kei, but I do love SID.
I've also got a thing for indie artists like School Food Punishment, DUSTZ, Swinging Popsicles, Waffles, Over and Under, and Lolipop World.
Annnnd as if this post wasn't rambling enough, these are songs I happen to really love as well:
MiChi - Change the World, YOU
Tohoshinki - Stand by U, Survivor, Share the World, Bolero (love this song
so much)
GReeeeN - Setsuna, Ano Koro Basho
2BACKKA - Namida, Harebare
UVERworld - kokorozashi, Gekidou, the truth, UNKNOWN ORCHESTRA
Mr. Children - GIFT, Hanabi, Kuchibue, Sign, HERO
Porno Graffitti - Neo Melodramatic, Agehachou, Koyoi Tsuki ga Miezu Tomo
BONNIE PINK - Water Me (could not stop listening to this for ages)
Kimaguren - AiNEED, LIFE, Moshi Kimi to
THE ALFEE - Faith of Love, Dear My Life, Juliet
Perfume - One Room Disco, Dream Fighter, Edge
Capsule - JUMPER, Music Controller (remix version is my favorite)
The Back Horn - Requiem, Wana, Kakusei
HIGH and MIGHTY COLOR - goover, Kirakira Summer, TOXIC, ROSIER
Ryohei Yamamoto - Fly, One Love, Relisten
Tourbillon - Break the Chain, Lily
flumpool - Over the Rain, Dear Mr. & Ms. Picaresque
And you know regular music is boring when three K-On CDs top the Oricon charts.
...or that the otaku market has just gone way up. :O