I'm in the early stages of building an underground steampunk cave home, and "futureproofing" is one of my design principles. I'm going with a very open floor plan, on the concept that it's easier for people to add in walls than to take out walls that were never designed to be removed (and may consequently be providing structural support). I'm not including any drywall; the exterior walls, a pozzolonic concrete, will be pressure-washed to remove the cement from the surface, exposing the aggregate. All piping / conduits will not only be visible, but shown off as part of the style (as is typical for steampunk). If someone wants to change something that they can't just feed into an existing conduit, they won't have to rip out the drywall, change what they want to change, reinstall the drywall, and then repaint. Plus, there can be no "critters" living in the crawlspace when there is no crawlspace.
Even if I never want to change the house, I want it to significantly outlive me, and whatever future owners are around may want to change things. Plus, it's kind of fun when you keep future owners in mind. For example, I plan to paint a really creepy, gigantic (meters across) blood-red sigil underneath the flooring - an inverse of the ægishjálmur (protection against all evil), pointing inwards as if to trap evil in, with some runic writing along the lines of "All May Enter, None May Leave" (hopefully my Old Icelandic is passable :) ). I hope that whoever owns the house after me and decides to redo the flooring gets a kick out of that one. ;)