I have a slightly different take on theft prevention.

Forget about you losing your stuff. Think about your friend, neighbor, or co-worker, with that 14 year old kid that has been having problems. He's the kid that going to ride off on your bike, or steal the light, or get caught by a cop digging through your cars glove compartment.

If you lock your stuff up well enough.... maybe the kid can (by no choice of his own)... stay out of trouble just long enough to clean up their act. And sometimes.... that's all it takes.