How is it possible
Full Moon Wo Sagashite not be in your list!! Its a GREAT show! Do watch it!
Other great titles that are concerned with romance theme are:
Pretear (13 eps - short & sweet. After wathcing this show, I always feel refreshed. Love this series!)
Ashiteruze Baby (touching story)
Da Capo
D.N.Angel (another great series!)
Fruit Basket (Light-hearted)
Love Hina
Mamotte Shugogetten
Marmalade Boy (many eps but one of the greatest romance anime: a roller-coaster ride)
Tsubasa Chronicle (beyond excellent! not complete but season 2 is coming real soon)
Ultra Maniac
Karin (still watching it.. but promising)
Check
AnimeNewsNetwork for its synopsis.