Some may disagree, but I thought this dramas had the perfect ending:
Taiwanese:
Autumn's Concerto
Fated to Love You
MARS
ToGetHer
MoMo Love
Drunken to Love You
Japanese:
Hana Yori Dango
Nagareboshi
Innocent Love
Nodame Cantabile
Korean:
The Princess' Man
You're Beautiful
The Moon that Embraces the Sun
Stars Falling From the Sky
There are some Chinese dramas that I thought had the perfect ending, but perfect for the story and not perfect in terms of happy ending so I won't include any here.
Good luck finding what you are looking for! =D