I think a variation on mattress stitch works well here. By that I mean that you're not really seaming the two pieces together one stitch to one stitch, more like 3 edge sts to 4 stockinette. Under the Free Videos tab at the top of the page, Tips, is a video for mattress st if you'd like to see it.
I've also put the seam between the band and the sweater body, picking up at the very edges to make a flatter seam and that works well too.