There are some wonderful books out with designs in them. One is called, "Hooked on Quilting". It gives you some really neat options to consider for this quilt. I can see feathers and echoe quilting easily on this quilt. It all depends on how much time and quilting you want on it.
What you can do is print out a picture of your quilt and use a overlay sheet of plastic to doodle in the designs. Then if you don't like that just take a new sheet and try again. I think once you begin doing this, it will become apparent to you which design you like best. You sometimes have to think of it as a whole cloth with designs on it ignoring the smaller seams.