Unfortunately I have to agree with Frax, I had a car I spent a good few hundred on a fancy new security system and came down one night to find the alarm going off and holes in the doors where someone's little angel had put a screwdriver through them. Best bet in my book would generally be overt measures, disklok being a good one, get some smartwater stickers if you can for the windows and it can't hurt to put a tracker in case you need to recover, should the worst happen.
Deadlocks they only find out about after they try and break in, and they wil just use a window.
Failing all that, a very loud alarm, big dog, decent rifle and park it on your private range behind your house.