From what I've read a good safe and insurance will be the simplest and most effective. As well as a list and receipts of valuable items
True, but the best security is in layers,
and a lot of stuff isn't replaceable with insurance and a receipt.
Even a safe can be broken into if given time.
The KEY is to rob the thief of time and cause them as much hassle as possible so they have less time to spend robbing you.
Re-enforced doors with double tumbler dead bolt locks add to this hassle.
The thief either has to take more time and risk being seen breaking it in, or be forced to go in and out of a window.