Wait, your second quilt? Ever? That is just beautiful and you've done a great job! If i were having someone that is experienced in FMQ (I'd be too scared to try it myself), I'd do straight line quilting on the colored fabrics and I agree with Jo, an echo fan or something would be perfect. If it were me, I think I'd use white thread on the white fabric so that it will give texture to the areas but not draw away from all the beautiful blocks.