Depends on your budget! If you're able to do a custom or light custom rather than an all-over, I'd be might tempted to use a 'celtic' design. Here are some examples from Ann Bright designs (not affiliated, but love her designs!) -
http://www.annebright.com/shop/search/?keywords=celtic - either an allover (pantograph) or one of the designs in the 'block', with line dancing in the little squares surrounding the block, and feathers in the white circular areas.
I'd ask for a light thread - have your long-armer puddle some different threads on the quilt so you can see how it will show up when quilted.
Your long-armer will have suggestions for sure, ask for ideas. They may have samples of designs they've done before. One of the things I like to do - I have a piece of plastic (think of the plastic used to cover tablecloths) that I've bound with painter's tape (so I know where the edges stop) - I use crayola washable marker to audition potential designs - draw them out - to preview how they look on the quilt.
Have a good discussion with the long-armer, be sure you understand and agree with the quilting plan!
Beautiful quilt!