I have three- two "permanent" and one portable. For the permanent ones I stapled cheap flannel to a bare wall - one is behind my machine in my studio (which was the master bedroom) where I can easily put up and take down blocks as I work on them. The other is in the living room, which is now a big sewing room where my friends and I quilt on a regular basis. The third is a piece of flannel backed oil cloth from Walmart - I stapled pieces of velcro (the hook side) to the front edge of a couple of bookcases then sewed the corresponding loop side to the edge of the oilcloth (in my studio). When I need a portable design wall for class or just for a project that doesn't need to be out all the time, I hang up the oilcloth and do my work...when I need to take the work some where else or put it aside for a while, I roll up the oilcloth from the bottom, take it off the bookshelves and off I go. This works great for class projects, etc. (I don't have a huge house, I just live alone and decided that wasting space on traditional functions was...a waste...)
And I wouldn't live without any of them now that I'm used to them.