Well, it depends! What was in the car at the time it was broken into? Personally, I would want to have an angry, very hungry Rottweiler kept in the car just to give a thief the horrific surprise he or she well deserves. Most of us don't have the proverbial Rottweiler, so we have to think of other ways to survive an invasion of our personal privacy.
Suffice it to say here, that most auto insurance policies have very specific disclaimers about personal property coverage or lack thereof. When personal property is stolen from the inside of a vehicle, many believe it would be covered by the auto insurance policy. This would generally be incorrect.
Vehicle theft is covered under your Comprehensive coverage if you have purchased that coverage. Covered property inside a vehicle would be property, which is factory manufactured and is attached to the car and functioning as the automobile maker intended. Such as the factory radio and factory installed speakers. Custom installed radios, speakers, CD's, tapes, laptops, radar detectors, cell phones, videos, DVD's, clothing, leather jackets, shoes, suits, cleaning, laundry, and any other personal property is almost never covered in a standard auto policy. You can purchase coverage at CarInsurance.com for Customized Personal Equipment that is installed in the vehicle.
You should check for your vehicle registration, insurance identification card, and any personal information that can identify you. You may want to purchase identity theft insurance to protect your private information.
Sometimes special coverage can be purchased for items inside the vehicle, but the cost may be prohibitive if you are only trying to cover your CD's, or a few tapes. Many times a claim can be made with your homeowners or renters policy to cover personal items inside your vehicle, like a laptop or computers.
Several things can be done to avoid getting broken into. One thing to do is to keep any valuables out of sight. A thief is looking for the easy score. He may spot an iPod, or some other item he wants in your car but if your car has an alarm he will not be nearly so inclined to go after it. Lock your doors and make sure your car alarm is set and operating every time you leave your vehicle. Also, put valuables in the trunk, or otherwise keep them out of sight.
If you have to leave something in the cabin of the car, then cover it with your sweater or light jacket. Just keeping stuff out of people's range of vision will help a lot. Don't leave your windows open, or even cracked open an inch. Vulnerability is what the opportunist is looking for, and if you don't give it to him, he will go on down the street looking for someone who has left him or herself vulnerable. Thieves are looking for that blinking alarm light, or some other indication that the car is protected.
Park your car in well-lit areas with lots of people traffic around it where possible. If you are parking in dark alleys and empty lots, then this is a golden invitation to a car thief, or to be broken into. Don't go into the area you are going to park while you are blaring your stereo system loudly. This is just an advertisement that says "Hey, my car is here, come and steal my fancy stereo system and speakers."
If you are broken into; don't panic, call the police, get a police accident report from them, and call your insurance company. If there is broken glass or damage to the car when it is broken into, then that would typically be covered, minus the deductible, assuming you do have the comprehensive coverage.