over all of them my favorite is UVERworld
YUI, Rie fu, Mai Hoshimura, BENI and NICO Touches the Walls are awesome. Not really into J-music, so...
Kalafina, FictionJunction, Yui, Rie fu, Matsushita Yuya, Utada Hikaru, Ikimono Gakari, Last Alliance, Ken Hirai, Scandal, UVERworld, The GazettE, Aqua Timez, Kokia, Vocaloid, Supercell, Do as Infinity, Haruna Luna, Fripside, Sound Horizon, Mizuki Nana, Maaya Sakamoto, 2Backka ^__^
Group: Malice Mizer, An Cafe, The Gazette, AKB48 Singers: Gackt, Hyde, Miura Ryosuke, Shirota Yu, Hikaru Utada, Ai Otsuka
churian wrote: my ultimate favourite is GReeeeN! i just fell in love with the ROOKIES theme song and started loving them ever since


Argh I forgot to put GReeeN in my list. I fell in love with them through Rookies too. XD
Utada Hikaru Koda kumi SMAP EXILE J Soul Brothers L'arc en ciel B'z UVERworld,
I'm in love with voice of Ozaki Yutaka - pure perfection. But in general I'm a big fan of heavier sounds so my favourites (for today, or at least next few weeks) are Onmyou-Za, Kagrra and Inugami Circus Dan.
I'll try to narrow it down... lol

KAT-TUN, ONE OK ROCK, EXILE, J Soul Brothers, Miyavi, Miura Daichi, Matsushita Yuya, SCANDAL, Nakashima Mika, AAA, Arashi, Kis-My-Ft2, Alice Nine, SALU, AKB, flumpool, girugamesh, Kyary Pamyu Pamyu, S/mileage, Amuro Namie, SuG, Dazzle Vision, BACK-ON, ect.

Honestly, the list can go on forever...
Berryz kobo and Morning Musume ^^
I don't listen to j-pop, but when it comes to j-rock it would definatly Dir en Grey. I've seen them live in 2009 and and I hope they'll come back to The Netherlands.
Sooo glad I discovered J-Rock back in 2008. Now it seems like it is the music that defines who I am, along with K-pop!

Speaking for both J-rock and J-pop
My favorite singers and duos are:
Utada Hikaru, Miyavi, Kanon Wakeshima, KanonxKanon


Favorite bands:
Alice Nine, The GazettE, SCREW, An Cafe, Versailles, Acid Black Cherry
One Ok Rock is my absolute fav at the moment, then there's the 'old' Girugamesh, and the unfortunately disbanded D'espair's Ray. :) When it comes to J-pop I don't really listen to it anymore but Ikimono Gakari is nostalgia. Most people know them from the Naturo ost 'Blue bird', but their other songs are really good too~ :)
My favorite band is L'arc en Ciel. A friend of mine introduced it to me in high school and when I saw their amv of fourth avenue cafe I was instantly hooked! <3 Another one of my faves is KAT-TUN, I especially like Kamenashi Kazuya. And ever since I watched Rurouni Kenshin the movie, I've started to like One Ok Rock! (>.<) I also like Yui and Crystal Kay :D
AAA or Attack All Around is my favorite jpop group, although they're not quite as well known as some others. But recently I've gotten seriously into ONE OK ROCK. And I really love Rock'a'trench too!
I'm happy to add Yoshida Brothers and RIN, I adore traditional sounds in general so listening to this kind of music from Japan is a pure bliss :)