People often say to me - "I've got encryption, so I'm protected," or "I always use a laptop lock," so I'm protected.
In response I always remind them that laptop security should be looked at like a three-legged stool. If any of the three legs are missing, the stool falls over (unless the person on the stool is a member of the Beijing Circus, but that's a rare exception).
What are the three legs?
The first leg is Physical Security, like a laptop lock and/or an alarm on your laptop bag. If you're leaving your machine, lock it down!
The second leg is Data Protection like encryption. If your machine does get out of your control and someone nefarious removes your hard drive, you can be "reasonably" confident they won't get at your data. (I say "reasonably" because we've all seen the laptops at airports on in presentations where the password is written on a sticky note stuck to the machine!)
The third and final leg on the stool is a Protection Solution like AT-p. If your machine fails to check in to the monitoring center after a certain length of time then presto it bricks. Or if you know your machine is lost you can send it a poison pill and lock it down.
How many legs does your stool have?