No I find alarms give you a false sense of security. If I do get something I will design it myself. Most alarms can be disarmed fairly easily with the simplest of tools.

If you want an alarm for safety build one yourself. There are enough sites out there and books in the library that will teach you the basics of a good security system. You can spend under $50 and make your own ignition lock that you can only unlock from a keypad.