As for me, every girl in anime are cute and great!
OK, almost great... Though don't have a favorite one (-_-)
At the moment one of my 'top 10' characters is:
Izumi Konata from Lucky Star
I think the best gag character I ever seen!
(If the image doesn't shows up, so look on the google <(^_^)
I'll try to make sure that the picture won't be deleted.