Hi, Annette, I was thinking about your log cabins as I was looking at Alex Anderson's book, "Beautifully Quilted" this afternoon. Amongst her many "Guidelines" she says:
"It's okay, and in fact perfectly fine, to cross over seam lines of pieced units."
and:
"It is nice to mix geometric lines with soft, curved lines. That is why you will often see gridded backgrounds used with fancy motifs. They work well together and act as complements."
So really, anything goes, and you can mix it up. I suppose the best quilting design is the one we will actually do, isn't it? I became a big fan of the turkey tracks/crows foot stitch when I needed to finish a quilt in a hurry. I learned it from our friend Sara Vincent here on the board: http://www.quiltingboard.com/posts/list/1753.page
Also I read in Ruby McKim's book recently about string-pieced quilts that are simply quilted with basting stitches. Because they are mostly seams, I suppose! And you know what? I bet they are beautiful!
Ruby also says, "The design of your patchwork will largely determine the design used in quilting. Angles with angles and curves with curves, does not always hold true as most piecing is angular and much quilting is curves. Large plain blocks make the major demand for ornate quilting, while the converse is comfortingly true. That is if your piecing is elaborate the quilting may, yes, must be simple!
Happy quilting, Annette, and do let us see! Love from Marcella