AFTERSCHOOL, Brown Eyed Girls, RAINBOW, T-ARA, RaNia, Mika Nakashima, SPYAIR, SuG, ViViD, Piko, SKE48, ACID BLACK CHERRY and AAA

asian artist
perfume..
akb48..
shoujou jidai (casual listener and only liking their japanese ver)
2ne1 (only liking FIRE) lol...

western
RIHANNA...

Asian
Sound Horizon
Kyary Pamyu Pamyu
Meisa Kuroki
Sunny Hill
Dear cloud
Alex from Clazziquai Project
MAA

Western
Adele
Taylor Swift
Woodkid
Claudia Brucken (Songs from L.A Noire OST)
Emily Browning (Songs from Sucker Punch OST)

became fan:

After School
Jay Park
IU
J. Cole
SNSD

became stan:

Justin Bieber
SISTAR

thats about it

Leessang
Sunny Hill
10cm
W&Whale
Winterplay

mostly indies artist :roflmao

Foster the People
Kakkmaddafakka

& I am back into the Koda Kumi fandom.

Asian
ONE OK ROCK
SNSD (well I listened to them a bit before but now I really love these girls :heart)
T-ARA
Daichi Miura
IU

Western
Nicole Scherzinger
Adele
Kat DeLuna
The Pretty Reckless

well,not a fan but interested in the music:
Kyary pamyu pamyu
MAA
Utada (i know her before but i really love her music since this year)

TOKYO GIRLS' STYLE
May'n
SKE48
SDN48
NMB48
Buono!
KARA
AKB48 sub-units (No Sleeves, Watarirouka Hashiritai, Not Yet, DiVA)

MAA
Kyarypamyupamyu
f(x)

iamamiwhoami
Nicola Roberts
Feist

Only AKB48... (I think... :P)

Oh this is gonna be fun...

KyaryPamyuPamyu
★STAR GUiTAR
Sakanaction
Nothing's Carved In Stone
Meisa Kuroki

And others...

Asian:

Brown Eyed Girls (casual listener to fan)
Wonder Girls

Western:

Glee Cast (kind of counts I believe)
Jessie J
Lily Allen (casual listener to fan)
Chisu
Demi Lovato
Pixie Lott (only possible, because I've only just started really enjoying her music, so not quite a fan yet)

It was kind of a slow year for Asian music for me. I've mainly just listened to new releases from groups I already liked before.
I got much more excited by Western music this year I found.

Asian:
2NE1
BIGBANG
G-Dragon
Kalafina


Western:
Amaranthe
Greyson Chance

Koda Kumi! lol. I gave her another chance this year and fell in love.

SNSD!
LOL! i've never thought i could get a SNSD fever and it came unexpectedly since i saw Yoona!^^!

*Kalafina
*ayaka
*Tohoshinki (the old and the new one)
*JYJ
*Perfume
*2NE1

wow a lot! but REAL FAN of
would be
Meisa Kuroki
Mika Nakashima
Mai Kuraki
Kara
Orange Caramel
AKB48
Bang Yong Guk
Chi Chi
Chocolat
Itano Tomomi
L'arc en Ciel
Rainbow
Song Ji Eun (but i loved Secret so long ago :3)
TABLO!!! <3

B1A4
A Pink
Kyary Pamyu Pamyu
Rainbow
Girl's Day


That's all I can remember lol