Well, I'm a newbie on this forum (lurked a lot, though xD), but I'd like to say that I'd love having iridium-reinforced things (stone, glass, door etc) which are unmovable by pistons, take a lot of time to break (something like 5 minutes with a diamond drill) and are nearly explosion-proof (yes, nearly, like in "10 reactors full of uranium can still blow a layer of it" XD)... a house (or a chamber, in relatively early game) protected with something like a 20 digits combination lock should be absolutely safe, then. And I love combination locks =P