This quilt to me screams "modern". I agree with Bree, lots of closely spaced parallel lines going in different directions in each of the big white areas (also known as negative space). Google images of modern quilting or modern quilting in negative space and you will see loads of examples. It is super easy to do and will give the quilt fabulous texture.
You could also try your hand at breaking up the area using Angela Walters tile quilting technique if you want to get adventurous.
http://www.quiltingismytherapy.com/p...ilting-design/