If my guns were stolen I would start with the police and filing an insurance claim. Before I started replacing the guns I would re-evaluate my storage solutions and try to improve the security of my firearms. This may mean using a large part of the insurance claim to buy a better safe and possibly improving the home security system. Once I feel that I have made it as difficult as possible for them to be stolen again I would begin to replace the firearms. I think it would be foolish to run out and replace everything right away only to leave them vulnerable to theft again.
In the event of fire, flood, or other natural disaster I will make sure I have a roof over my head before replacing them.