Well you know orianna The Girl with her little pet, which really IS heavy, she does not have such a tremendous power like some other ap chars like karthus but thats why you will have to cover the lack of ability dmg with attack speed because of her passive ability so try making a full build of this TROLL girl and you will probably be... Legendary

Please vote :)

Pros
She is ranged and her abilities are "ball do this and ball do that" so she is practically out of battle
She can help herself/the team
She can take advatage of the team's potition
She is very good at close range too she is not as good as she is in a mid range battle
Cons
well if the enemy catches you then good luck :P
if orianna gets ganked from both sides then there is no way to escape
she is not very good at ganking(i mean she doesnt do anything special and she is also AOE)