recently attended the Sewing Expo in Puyallup, Wa. While there i attended a couple of lectures by Alex Anderson, one on quilting the quilt. Her guidance: the quilting should be about the same density over all, echo a shape found within the quilt fabric or piecing, fancy stitches don't generally show up in the geometric piecing very well so keep them for the canvas of bigger spaces/sashings etc. look for patterns in nature, architectural designs etc. She has a book out on quilting and recommended one called, "Finishing Touches" by a deceased Mennonite quilter she learned from early in her career.
i took pictures of mosaic tiles, windows, fences, churches and more when i travel and use those for quilting inspiration.