This is a real tough one because there are so many that I love, but here's a rough list:

1. Moments - Ayu
2. NEVER END - Namie
3. Winter Love/Everlasting/Meri Kuri - BoA
4. YOU - Ayu
5. I WILL/Wishing on the Same Star - Namie
6. First Love/Final Distance - Hikki
7. Tobikatta wo Wasureta Chiisana Tori/Everything - MISIA
8. Precious - Yuna Ito
9. Ikutsuka no Sora - Shibasaki Kou
10. you - Koda Kumi

1. Who - Ayumi Hamasaki
2. Unmei - Koda Kumi
3. Fair Wind - Yuki Koyanagi
4. M - Ayumi Hamasaki
5. mink - Hold on to a dream
6. Seasons - Ayumi Hamasaki
7. Precious (Special Version) - Yuna Ito
8. ETERNAL SNOW - Changin' my Life
9. Mikazuki - ayaka
10. Endless Story - Yuna Ito / Yume no Uta - Koda Kumi

Sakurairo Maukoro - Mika Nakashima
Precious - Yuna Ito
Yuki No Hana - Mika Nakashima
Will - Mika Nakashima
Renai Shashin - Ai Otsuka
Endless Story - Yuna Ito
Oborozukiyo~Inori - Mika Nakashima
I Believe - ayaka
Kairo - Utada Hikaru
Winter Love - BoA

And Sunao Na Mama will probably become my favorite after listening to it more. Mika is the ballad queen. :)

wow this is hard - ok here's my top 10 J-Ballads -

#1 - Dearest - Ayumi Hamasaki
#2 - Will - Mika Nakashima
#3 - PRIDE - Ayumi Hamasaki
#4 - PLANETERIUM - Ai Otsuka
#5 - Oborozukiyo ~ Inori - Mika Nakashima
#6 - Cherish - Ai Otsuka
#7 - Hi no Tori - Mika Nakashima
#8 - 1000 no Kotaba - Koda Kumi
#9 - Kumo no Ito - Mika Nakashima
#10 - Fukai Mori - Do As Infinity
Mika is definitly the ballad queen for me ^_^

I don't really know too many ballads beyond like Ayumi & Namie, and some Koda haha well I do I guess but Ayu would just dominate all my charts anyway so there's no point but I'll do it anyway! XD

1. Moments - Ayumi Hamasaki
2. CAROLS - Ayumi Hamasaki
3. teddy bear - Ayumi Hamasaki
4. Can you celebrate? - Namie Amuro
5. No way to say - Ayumi Hamasaki
6. JEWEL - Ayumi Hamasaki
7. HANABI - Ayumi Hamasaki
8. Never end - Namie Amuro
9. M - Ayumi Hamasaki
10. Dearest - Ayumi Hamasaki
11. a song is born - Ayumi Hamasaki
12. Love ~Destiny~ - Ayumi Hamasaki
13. SEASONS - Ayumi Hamasaki
14. First Love - Hikaru Utada
15. Yume No Uta - Koda Kumi
16. A Song For XX - Ayumi Hamasaki
17. Sakurairo Maukoro - Mika Nakashima
18. Wishing On The Same Star - Namie Amuro
19. Four Seasons - Namie Amuro
20. This Love - Angela Aki

(Yeah I did 20 ahah oh well, it's cool)

-Most of these will be Ayumi, just as a warning.-
1. Jewel - Ayumi
2. Heaven - Ayumi
3. Dareka no Negai ga Kanau Koro- Utada
4. M, Acoustic Orchestra Version- Ayumi
5. Hanabi - Ayumi
6. Tsuki no Uta- Gackt
7. This Love - Angela Aki
8. Flavor of Life, Ballad Version - Utada
9. Seasons, Ayumi
10. Dearest - Ayumi

You - Koda Kumi
Memorial Address - Ayu
sayonara - gackt
aishou - koda kumi
daisuki dayo - ai otsuka
kingyo hanabi - ai otsuka
dareka no negai ga kanau koro - utada hikaru
heaven - ayu
yume no uta - koda kumi
planetarium - ai otuka

No order..ill edit later when I get them in order

Believe - Kumi Koda
Hands - Kumi Koda
Kingyo Hanabi - Ai Otsuka
Daisuki Da Yo - Ai Otsuka
Renai Shashin - Ai Otsuka
You - Kumi Koda
Jewel - Ayumi Hamasaki
Heaven - Ayumi
Itoshi Hito - Miyavi
Love Letter/Ash - Gackt

Must have the Gackt in there..I love those two songs..so MUCH!

Free & Easy - Ayumi Hamasaki
My Dear - sifow
kiseki - Koda Kumi
Planitarium - Ai Otsuka
Wishing On The Same Star - Namie Amuro
Apple ~Akai ringo~ - sifow
Tsuki no Uta - Gackt
FINAL DISTANCE - Utada Hikaru
end roll - Ayumi Hamasaki
JEWEL SONG - BoA

1. Hamasaki Ayumi - Key ~eternal tie ver~
2. Utada Hikaru - First Love
3. Ozaki Yutaka - I Love You
4. Oda Kazumasa - LOVE STORY wa totsuzen ni
5. Mr.Children - Kurumi
6. Nakashima Mika - missing (I definitely preferred her rendition to the original)
7. Tokyo Jihen - Rakujitsu
8. Hirai Ken - Hitomi wo tojite
9. Every Little Thing - Samidare
10. Garnet Crow - Kyou no kimi to asu wo matsu

Momentum - ayumi hamasaki
Key - ayumi hamasaki
jewel - ayumi hamasaki
rainbow - ayumi hamasaki
part of me - ayumi hamasaki
graduation - speed
hands - koda kumi
be my last - utada hikaru
sakura drops - utada hikaru
deep river - utada hikaru

it is gonna be 10 ayu ballads for me :)
heaven, m, carols, voyage, forgiveness, dearest, who, for my dear, jewel, seasons

this is tough here goes
no order

1) HEAVEN - ayu
2) Moments - ayu
3) No way to say - ayu
4) Winter Love - BoA
5) Truth - Yuna Ito
6) Flavor of Life ~Ballad Ver~ - Utada
7) First Love - Utada
8) Yume no Uta - Kuu
9) you - Kuu
10) Sakurairo - Angela Aki

tats not all... haha
i think ayu has the best ballads for me thou..haha..but to be fair i have included most artiste i listen to

(actually i never realized how nice Kuu's ballads are until BOUNCE&LOVERS)

1. Ayumi Hamasaki - Heaven
2. Utada Hikaru - First Love
3. BoA - Everlasting
4. Ayumi Hamasaki - Hanabi
5. Ai Otsuka - Planetarium
6. Ayaka - Mikazuki
7. Yuna Ito - Precious
8. Utada Hikaru - Flavor of life -ballad version-
9. Koda Kumi - Unmei
10. Ayaka - I believe