Quality? Easily. But popularity? Pokemon was untouchable at its peak. The first movie opened up at #1 and made $170 million WW box office. It was featured on the cover of TIME, and there's STILL a Pikachu float at the Macy's Thanksgiving Day parade. It can't be beaten.
Skahugan no Shana
Karin
Blood+
Kimi ni todoke
Jigoku shoujo
Sekirei
Inuyasha
Kantanagatri
True tears
SailorMoon
Eureka seven
Panty&stocking
Yusoga no sora
Airtv
Clannad
Arakawa Under the Bridge
B Gata H Kei
Bakemonogatari
Chobits
Canaan
Card Captor Sakura
Haré+Guu
Toki wo Kakeru Shoujo
Higurashi no Naku Koro ni Kai
Ga-Rei -Zero-
Mitsudomoe
Tengen Toppa Gurren Lagann
Tenchi Muyo! Ryo-Ohki
Kobato.
Kannagi
Michiko to Hatchin
Hime-chan's no ribbon
Urusei Yatsura
Oruchuban Ebichu