I've long wanted to run DC in my house, but there's no standard. Do I run 120v, 240v, 5v, 12v? Which interface do I use? Barrel connectors, USB, cigarette lighter? If we have a large-scale movement to household DC, we'd have these things hammered out without me rewiring every appliance.<p>If these obstacles were overcome, almost everything in my house could run on DC. Most stuff either converts to DC internally, or doesn't care.