Yeah, I wouldn't even consider her a favorite character by any means. She's cute and everything, but the source of the Show's humor seems to come from everyone besides her.
Now, Doof... Doof's the reason I watch! And I can't even begin to list my favorite Doof moments. Getting beaten by a potted plant is certainly on there... hating the fact that he can't even find anything remotely to dislike about Christmas (turning relatively every single cartoon "_______ Saves Christmas" episode on its ear). There's so much comedic gold there. And that's just that character. Also love the play between Buford and the Indian Kid (His' names something like Radjeed or something, right?)... Even when Candice loses it trying to bust her brothers sends me rolling on the floor.
The "Indian" kid (as you call him) is Baljeet Patel.
She's not a bad character, Isabella, by any means... I just find everyone else outshines her.