The material is a sturdy home decor fabric, and the stripes are actually wedges: you can see the fabric laid out flat here on Ikea's site.
I like to choose something fun for the waistband facing: however, it is very tough to compete with rainbow fabric in the fun department. I ended up going with a scrap from one of my all-time favorites, my first Butterick 6149:
Poor schmeebot will not get her skirt until I make it a traveling companion, so expect to see another Pacific moon soon. But first, I have a few other projects in the pipeline!