I had my Civic stolen a couple of years ago, and now use various theft-deterrants on my wife's Civic.

The Club
The Autolock
Alarm
Fuel cutoff

I know people say the club/autolock aren't going to necessarily stop all thieves, and that's true. However, time is the enemy of the thief, and if it take a thief 10 min vs. 5 min to steal a car, he'll most likely go to the easier one.