What are the first albums you heard by your favorite J-Pop artists?
For me,
Ayu - MY STORY
Kuu - Black Cherry
Namie Amuro - PLAY
Utada Hikaru - Exodus
Ai Otsuka - LOVE PUNCH
BENI - COVERS
Kyary Pamyu Pamyu - Moshi Moshi Harajuku
BONNIE PINK - Golden Tears
Ami Suzuki - Supreme Show
Just to name a few...

I would have included Kana Nishino but I received LOVE one., to LOVE, and Thank you, Love all together so there wasn't really a 'first album' per se.