I simply tossed mine on an SD Card.  The SD Card is not in a safe or anything, but of course, my wallet is encrypted (4096 RSA).

The private key I used to encrypt the the wallet is also encrypted w/ another key pair and stored offline.  Lastly, the actual encrypted wallet files are obfuscated in source code archives - basically hiding in plain sight.  Casual thieves probably wouldn't even find the encrypted wallet/key files.  Personally, I'm more concerned with fire, so I have things stored on Google Drive in a similar format.  When I have more funds transitioned to bitcoin, I'll think about picking up a fire-proof safe.