It depends on whether you want to see the stitching or not... STID is a stitch you don't really see (you aren't supposed to, anyway!) so I don't use it much. I'd rather see the quilting stitch and use it to add beauty to the quilt.
You can do curved lines with a walking foot too and lots of neat designs. You don't have to stick to just STID. Check out this website for more ideas with a walking foot:
http://blog.petitdesignco.com/2012/1...-quilting.html