Ayu:
M
evolution
SURREAL (the list will go on forever xD)

Shiina Ringo:
Meisai
Yume no Ato (HF version)
Honnou
Sakana

RURUTIA:
Traumerai
Senichiya

Kuu:
1000 words
Real Emotion (That's what got her made after all right? xD)

I'll pick one or two from each singer~

Ayu - evolution / SEASONS
BoA - LISTEN TO MY HEART / VALENTI
Kuu - you / Cutie Honey
Namie - CAN YOU CELEBRATE? / Chase the Chance
sifow - Carat (in the gyaru regions LOL)
Rina Aiuchi - Koi wa Thrill Shock Suspense
Utada Hikaru - First Love

Rina's single was a big hit when it was released, and is still like one of the biggest songs of her career ^^;

how could I forget Kotoko? ; ;

KOTOKO:
Re-sublimity
Agony

^^

Ayumi Hamasaki
July 1st (first J-Pop song I ever heard)
SEASONS

Utada Hikaru
Passion
FINAL DISTANCE

Mika Nakashima
雪の華
GLAMOROUS SKY

OLIVIA inspi' REIRA
a little pain
Wish

Maaya Sakamoto
指輪

Lots of similarities in this thread, I see. :)

Ayumi - evolution, SEASONS

hitomi - LOVE 2000

Utada - Hikari, First Love

Koda Kumi - Cutie Honey, 1000 no kotoba

I would have to say...

Sakai Noriko - Aoi Usagi

Kiroro - Best Friend, Mirai e

globe - Departures

Kahala Tomomi - I'm Proud

TRF - CRAZY GONNA CRAZY (female lead? ahaha.)

Amuro Namie - CAN YOU CELEBRATE?, body feels exit

ZONE - Secret Base ~Kimi ga Kureta Mono~

Morning Musume - LOVE Machine, Koi no Dance Site, Renai Revolution 21

Hamasaki Ayumi - Boys & Girls, M, evolution, A Song for XX (Dearest, Voyage, No way to say for winning the Japan Record Award)

Utada Hikaru - Can you keep a secret?, First Love, Flavor of Life -Ballad Version-, Hikari

Otsuka Ai - Sakuranbo, Planetarium

SPEED - White Love, my graduation

Kuraki Mai - Love, day after tomorrow; Reach for the Sky

MISIA - Everything

Nakashima Mika - Yuki no Hana, LIFE

BoA - Listen to my Heart, Every Heart -Minna no Kimochi-

Hirosue Ryoko (Okamoto Mayo)- Daisuki!

Hitoto Yo - Hanamizuki (good one Halla!)

Natsukawa Rimi (Moriyama Ryoko) - Nada Sou Sou

Every Little Thing - Time goes by

Koda Kumi - 1000 Words, real Emotion (I think these can stand the test of time, if anything)

Okamoto Mayo - TOMORROW

Hana*Hana - Sayonara Daisuki na Hito

Ito Yuna - ENDLESS STORY

Too much?

Ayu - SEASONS, Boys & Girls

Kuu - Butterfly, Cutie Honey

Otsuka Ai - Sakuranbo, Planetarium

BoA - LISTEN TO MY HEART, VALENTI

Mika - Yuki no Hana

Hikki - First Love, Automatic

98~05

ayu

Fly high
Depend on you
Moments
M
SEAOSNS
SURREAL
Because of You
Connected

kumi

m.a.z.e
Trust Your Love
real Emotion
Rain
Go Together

hikki

hikari
Automatic
Can You Keep A Secret?
Wait & See ~risuku~
SAKURAdorrpusu

BoA

kokoro no tegami
NO.1
kiseki
WINDING ROAD feat. DABO
Amazing Kiss

namie

Come
SO CRAZY
Namie's Style
Break the Rules