A : Ayaka, Alan, Avril Lavigne, Adam Lambert
B : Britney Spears, Bond, Black Eyed Peas
C : Celine Dion
D : Dream, David Guetta
E : Enrique Iglesia
F : Flo Rida, ferry Corsten
G : GReeeeN
H : Hiro (member of SPEED), Hamasaki Ayumi
I :
J : Jay Sean, JEssican SImpson,
K : Koda Kumi, Keri Hilson, Katy Perry, Kana Nishino, Ke$ha, Kenny G, Kris Allen
L : Leona Lewis, Kenny G, Lady Gaga, leah Dizon, Lindsay Lohan
M : Mariah Carey, Madonna, Mika Nakashima, MISIA
N : Namie Amuro, Ne-Yo, Nelly Furtado, NewS, Nick Lachey, Nickleback,
O :
P : Pink, Pussycat Dolls, Pitbull
R : Rihanna, Ricky Martin,
S : SPEED, Shontelle, Spontania, Son Dam Bi, Stan Walker, Suzuki Ami
T : t.A.T,u, Takako Uehara (member of SPEED), Taylor swift
U : Usher,
V : the Veronicas
W :
X :
Y : Yuna Ito
Z :

A: Ayumi Hamasaki / Avril Lavigne / alan
B: BoA / Bon Jovi (sort-of) / Britney Spears
C: Cyndi Wang
D: DBSK
E: Elva Hsiao / Eason Chan
F:
G: Goto Maki
H:
I:
J: Jolin Tsai / Jesse McCartney
K: Koda Kumi / Kana Nishino
L: Lady GaGa / Leona Lewis
M: My Chemical Romance / Muse
N: Namie Amuro
O: Otsuka Ai
P: Paramore
Q: Queen
R: Rainie Yang
S: Show Luo
T: Taylor Swift
U: Utada
V: Vitas
W: Within Temptation
X:
Y:
Z:

Ready for a big list? :D

A: Ayumi Hamasaki (duh)/ABBA/Adam Nickey/Above & Beyond/Alabaster/Ai Otsuka/alan/Ami Suzuki/Armin van Buuren/Ashlee Simpson
B: BoA/Betwixt & Between
C: capsule/Cold Blue/chum
D: Dan Stone/Daniel Kandi/DJ Amaya
E: Eiko Shimamiya/Every Little Thing/eufonius
F: Freezepop
G: GIRL NEXT DOOR/globe
H: Hilary Duff
I: Igor Sapunov
J: Jono Grant
K: KOTOKO/Koda Kumi/Kaori Utatsuki/KOJA YUKINO
L: Lia/Lady Gaga
M: m.o.v.e/Mat Zo/Maor Levi/Mami Kawada/MELL/Miley Cyrus/Miyuki Hashimoto
N: Nami Tamaki/Namie Amuro/Nitrous Oxide
O: OceanLab/Oliver Smith/The Orb/Origa
P: Perfume
Q: -no artist-
R: REDALiCE/Rita/Riyu Kosaka
S: Son Dam Bi/Sunny Lax/Super8 & Tab
T: teranoid/Temple One/T.M. Revolution/Thanatos/TWO-MIX
U: Utada Hikaru
V: -insert all Vocaloids here-
W: Wellenrausch
X: -no artist-
Y: YUI/YURIA/Yui Sakakibara/YOSHIMUNE SAUNDOTORAKKU
Z: -no artist-

...wow, I can't believe I typed that all out! As you can see I have a varied music taste, mostly Trance and Japanese Pop.

Avril Lavigne
Britney Spears
Chisu (Finnish female singer)
Don't have one ^^
Eminem
(f)x
Gwen Stefani
Hamasaki, Ayumi (you know, the reason we breath :lech )
Indica (Finnish female band)
Jojo // Jewel
Kent (Swedish male rockband) // Kokia
Loona - Hijo de la luna. All I have...
Michelle Branch // Melissa Horn (Swedish female country(ish) singer)
Namie Amuro
Otsuka, Ai
Peter Jöback (Swedish male singer)
Q, Stacey
Regina Spektor
Swift, Taylor
t.a.t.u
Utada Hikaru
Veronica Maggio (Swedish/Italian popsinger). Altough I only like one of her songs...
W
X
YUI
Z

This looks like fuuun

A: Ayumi Hamasaki / ayaka
B: BENI / Beyonce / Bowling for Soup
C: Christina Aguilera
D:
E: Enigma
F:
G: Gwen Stefani
H: Hikaru Utada
I: ICONIQ
J: Jade Valerie
K: Kumi Koda / Ke$ha / Katy Perry
L: Leona Lewis / Lady GaGa
M: Miliyah Kato / Mariah Carey / Maki Goto
N: Namie Amuro
O:
P: Pussycat Dolls / Pixie Lott
Q:
R: Rihanna
S: SHION
T: Taylor Swift
U:
V
W: Within Temptation
X:
Y:
Z:

A: Ayumi Hamasaki
B: Björk
C: Covenant
D: Depeche Mode
E: Eiko Shimamiya
F: Fangoria
G: Goldfrapp
H: HADOUKEN
I: Icon of Coil
J: Joy Division
K: Kaya
L: Lady Gaga
M: Madonna
N: Najwa Nimri
O: OBK
P: Prodigy
Q: Qntal
R: Róisin Murphy
S: Seiko Matsuda
T: t.A.T.u.
U: Utada Hikaru
V: Vive la Fête
W: Wynardtage
X: Xotox
Y: Yoko Kanno
Z: Z Prochek