Sedum sexangulare is as the name suggests; six sided. The foliage twists in a spiral up the tiny stems in a very pretty texture.
Although low growing, it can hold it's own against taller types and species. This isn't to say that it is aggressive, just assertive in its growth.
I also like the contrasting textures in a Sedum tapestry, or draping over the edges of a container.
Eventually one plant will root itself in an area of about 20cm (8-10") across to form a mat.