I would say that it depends on how much quilting you have in the rest of the quilt, if it's fairly closely quilted, closer than 2 1/2, I would do some quilting in the border so that it lays flat and doesn't puff up or get wavy. You could always just do straight or decorative stitching 1/2 inch from each edge, that would be simple, or if you prefer fmq, you could do a wave or a free form cable.