In hand quilting.. the knot at the end goes like this. Stitch x2 in the same stich..go inbetween the fabric for a good inch or 2..come up and cut. The long string at the end will get twisted and curled during the wash and WILL NOT come out.

As for Machine Quilting. I do backstitch at the begining and end. I'm also curious as to what others do with their straight line quilting. In the FreeMotion Quilt.. I know they advise doing 3 or 4 stitches in the same spot.. Right??