kill switch

I'm gonna go ahead and say what needs to be said. If someone REALLY wants your car. They will get it.

Locking your hood is a good idea. I'd install a set of hood pins in reverse or something to that general gist. You want the lock to be hard to get to, not visible unless they are really looking for it, and somewhere you can still get the key in it. Like behind the headlights.

BUT, as Inkjunkie said, someone will eventually see this conspicuous action and use it for their gain.

My plan of action, eventually is this: kill fuel pump relay, like 67Dart273 said. Ground coil negative through open cigarette lighter so they cant start it without it. And some kind of wheel disconnect hub. So you can just take the wheel with you and have you wheels cut as hard as possible to one side so its much harder to tow