Fuel pump, ECM, starter, cam sensor...a number of different kill switches one can do.
I have the steadfast column guard, a Viper 791XV, Lojack, 3 kill switches, a steering wheel lock, a throttle lock, a wheel lock, motion sensors in the garage and a Kimber.
If someone wants the car bad enough they're going to get it, the best you can hope for is to slow them down in the process in hopes that runs them off.
The way you park it can also be a deterrent, allot of car guys tend to want to back their car in the garage, keep the wheels straight, and be overly OCD about how it looks sitting in the garage. Park it straight in and turn the wheels.