Well, cars get stolen even in "good" areas. Some people just pull the coil wire when they leave, but that won't stop a thief from ripping things off on the inside of the car.
The first place they'll look for a kill switch is under the dash, in the glove box, and under the seats. Make sure it's well hidden, or it'll probably only slow them down for a few seconds. I always thought it would be funny to rig up a series of switches which all have to be positioned correctly in order to start the vehicle (i.e. 1 off, 1 on, 2 off, 1 on, in some random order..) then if the car did get broken in to but not stolen, I could laugh later on about how the thief probably sat there scratching his or her head about what the hell the right way to set the switches was.
Surprisingly, alarms don't seem to scare thiefs anymore. Their lookout will just play it off like they can't figure out the remote if somebody walks by, and the chances of a cop being around... well you know how that works. If your alarm has a pager that alerts you when the alarm trips, that's probably about as good as you can do.
Sorry to sound negative, but car theft is everywhere.. take pleasure in knowing you're at least 1 step ahead of 80% of the rest of the cars on the road which aren't equipped with any sort of theft deterrant.