I use fusible fleece - it won't have a lot of drape but my runners don't run off the end of the table so it doesn't matter. I also use it for placemats. I only buy it on sale because at 18", placemats add up fast on the yardage.
I like the fact that it is flat enough that nobody's glass falls over if they place it on the edge of the runner or the placemat. -Judy