This graph from Radagast's blog plots 'Art' across a matrix showing both spiritual benefit and artistic quality. While not intended as a representative survey it shows, interestingly, that popularity, quality and benefit are different and important aspects of Art. So you have the Lord of Rings (book) being popular, very good and excellent, while Star Wars (movie) while also being popular is neutral and poor. This chart is not intended to be definitive but it's an excellent starting point in making us think about Art and it's value.