I have a good 550 pound, concrete lined, fire rated safe. We don't just keep guns in it (I may or may not have a few), but spare car keys, car titles, birth certificates, spending cash, jewelry, etc. For me, a good investment for protection, and piece of mind when I'm not home.
On the other side of the coin, I had a buddy that built a false wall in his basement with an entry built into a large locker style cabinet (hidden switch) he hung old clothes inside. I doubt anyone without prior knowledge would discover it without hours of searching.
Busting thugs since 1992