ATX form cases...

Most mobo today are ATX form and so are the cases. My question is that is ATX form going to be around for a long time or is there hint at a different form. Is it reasonable to invest in a expensive ATX form case and reuse it over and over with upgrades after upgrades?

ATX should stick around for a long time (see chart below for sizes) the only thing that could screw it up is the power supplys (if we needed some sort of odd power requirement) but odds are they would still stick with it (cost to much to change)