I've become a big fan of triple borders recently- mid size inner, narrow middle, wide outer border. If you want to bring out more blue from the quilt, I would go blue-white-blue. If you want more red, then blue-white-red. You could also do white-blue-red or white-red-blue, but I don't think either of those would pop as much as a narrow white between two darker values.
Just my .02, adjust for inflation.
Great job!