There is no such thing as a fire-proof safe, but the more fire-resistant you can get, the better. I chose a Liberty Presidential (their middle of the road design), because one of my clients was burgled. They took his safe out of his business during a long holiday weekend. When it was recovered several days later, it had been sawed on, hammered on, attacked with a blow torch and thrown into a 30' gully and had been so heavily damaged that it couldn't be opened. My client sent it back to Liberty, at their request, to be covered under their warranty. The contents were recovered from the safe relatively unharmed and the factory replaced the safe with a new one.
"In a home fire, the peak temperature and duration of the fire can vary depending upon the size of the home, the materials used to construct the home, the response time of firefighters, etc. It is estimated that the typical peak temperature in a home fire ranges between 800 to 1200 degrees Fahrenheit. The typical time for firefighting authorities to bring a home fire into containment is estimated at 15 to 30 minutes."
http://www.libertysafe.com
Certainly nothing is safe from someone with enough desire and enginuity, but 90% of the criminals out there just need a good deterent.