A few weeks ago my home office was broken into and several items were stolen. Two of which were iMacs. My wife and I were privileged to assist law enforcement retrieve some of the items, one of which was a 20" iMacs. In light of this I have a few tips that will help you if you should suffer the same fate.
1. Store Documents in a Safe Place
With the purchase of your computer comes booklets, pamflets, stickers and tons of paper. Some of which you may consider pointless but don't be so eager to throw them out. Sift through all the documents you've received and ensure that you have a receipt, the serial number, MAC address and whatever else is unique to your computer.
Once you've identified all these documents place them in a waterproof container and store them on a elevated surface (like a shelf). DO NOT store in your laptop bag or the box the computer was shipped in! If possible scan the documents and save them in a cloud app like Google Docs. This information will be vital the minute your laptop gets stolen.
2. Implement a Back-Up System
It's great to have a external drive to back-up your files. However, in the event you drive is with your computer at the time when it's stolen say "Bye Bye".
I highly recommend the use of a third-party service, like Mozy, CrashPlan or LogMeIn Back-up, to archive your files. The ideal thing would be to use a desktop application to back-up to your external hard drive and then mirror that using web-based back-up service.
3. Install a Tracking Software
It's now time to ensure that wherever you computer goes you know. Install a tracking application like Prey Project, Adeona, Locate PC or LoJack for Laptops. The features will vary with each software, from giving you a screenshot to taking a photo of the perp. But one thing they all have in common is that they will notify you once your computer comes online, giving you an IP address - this you need to give to your ISP who will give the account details to the local police only.
While installing the tracking application be careful not to create a desktop shortcut, taskbar icon or a menu listing. You want the application to run in the background unbeknown to the perpetrator.
If you can afford to by LoJack for Laptops I recommend you do. Why? One of the main features of this application is that it writes itself onto the bios of your computer, which means that even if the thief wipes your hard drive and installs a another OS the tracking application will send out a distress signal while on the internet.
4. Auto Login (Optional)
Auto Login! Are you crazy? Yes I am... if the thieves boot up your computer and they are unable to access the computer due to a username & password they're just going to wipe your system and install a new operating system. If you computer boots up and gives them instant access to your desktop they'll get the feeling that it's smooth sailing and let their guard down. The minute they start browsing is the minute you'll get an ip address. That's what we want.
They may delete a few files and applications. However, you can protect your most important files by password protecting them.
5. Get Insurance (Optional)
If your computer is for more than recreation give a call to your local insurance company, choose an appropriate premium and insure your investment. In the event you don't get your computer back you can acquire another and use your archived files to quickly regain equilibrium.