General Car security

[Fiat1112]

So last night I heard a smash outside at 3.30 in the morning and I've jumped up only to see a guy running to a motorbike and speeding off. 20 seconds later he returns,takes his helmet off when parked up and then drives off again. Strange.

You guys got any idea of the best car security? I know nothing's gonna stop someone smashing the car in,but you know, a little deterrent?
Any ideas would be great thank you