Hamasaki Ayumi - LOVEppears or A BEST, since they're sorta the same..haha
Utada Hikaru - First Love
Luna Sea - PERIOD
Aiuchi Rina - Be Happy
ELT - force 4 (or whatever it was called)
Dragon Ash - viva la revolution
GLAY - Global communication

(i have very ecclectic tastes) :innocent

Sure you do.

Utada Hikaru - First Love...I mean, it's the best selling Japanese album ever
Ayumi Hamasaki - A Song For XX...because of the lyrics and how people started relating to her...the title track is really famous in Japan
Ayumi Hamasaki - LOVEppears...because the picture is topless (though her hair is covering it) and when it was released it was a huge, daring thing to do
BoA - Listen To My Heart...one of the most successful Korean artist Japanese debut albums.

Do As Infinity - Do The Best
H/\L - singles
Utada Hikaru - DEEP RIVER
ayumi hamasaki - *the new upcoming album*[DEFINITELY!!!]

well that's all from me, not many j-pop albums that i bought are essential...
most of them are kinda 'average'
those are the best

hmmm.... i noticed no one chose kinki kids album.. how sad... i think i will choose..
Ayumi's A Best
Ayumi's RAINBOW (cos it consists of my fave song HANABI~)
KinKi Kids' F Album
KinKi Kids' G Album

Luna Sea - Period
Luna Sea - Shine
Gackt - MOON
Utada Hikaru - Distance

Some of these albums aren't the least bit essential...

I think we need to look at that list of 100 top Jpop artists ranked by some Japanese music organization from a while ago....the one where Ayu was ranked 40~50 something.

Ayumi Hamasaki - Duty

Ayumi - Duty

Namie Amuro - Break The Rules

Anything Do As Infinity!!! Deep Forest, Song of Truth, New World....

BONNIE PINK - Even So
BONNIE PINK - Present

Do The Best... by DAI

A BEST and/or I am... by Ayu

huma-rhythm... by hitomi

Happy End of The World... by Pizzicato 5 (i think it's a good choice)

181920... by Namie Amuro

and i don't know what else... :no

Namie Amuro - GENIUS 2000
BoA - VALENTI
Onitsuka Chihiro - INSOMNIA
Ayumi Hamasaki - I am...