I would stay at Art of Animation, because the pictures of it are so beautiful. Port Orleans looks very promising, too. And I've walked through the Polynesian resort--beautiful beach, hammocks, great water slide, gorgeous lobby. Disney tends to do decoration right.
I guess it would depend on what appeals to you and your girls, but we always have a great time, no matter where we stay. We have stayed at Pop Century, All Star Music and Shades of Green. At Pop Century, as we were walking through the lobby, our daughter got 'recruited' for a Twist contest! At All Star Music, the drapes were made to look like sheet music. At Shades of Green, the shopping was the thing, as there is no sales tax. Each resort has its strengths.