I decided to activate the alarm system my house already has installed. Maybe I watched too many episodes of It Takes A Thief on the Discovery Channel - that show generally recommends everybody get AND USE an alarm system. Their point was an alarm dissuades a casual, opportunistic thief. Obviously, you can't keep out someone who is very determined, but an alarm system will make most decide it isn't worth the hassle and move on to some other victim. ;)
What was really interesting was how fast two experienced thieves can clear out a house. On the show, they would find a suitable target (and talk to the homeowner to get permission), rob the place, make security recommendations, and come back to check on the improvements. The interesting part of the show for me is the recommendation section, but the most exciting is the actual robbery, which they filmed for the homeowners and us to watch. Many times, they would zip into a house while the occupant was off doing some errand like grocery shopping or going to the post office, and essentially take 80% of the valuables in just 20 minutes. Jewelry was one thing, but these guys would also make off with big screen TV's, electronics off all sorts - one house had a small safe that wasn't bolted down, so they just took the whole safe! Another guy had a motorcycle collection and they just drove them onto the truck.
Anyway, with the alarm system I now have to visit the control panel every time I enter or leave the house. This really isn't too much trouble. Before leaving I shut all the doors, then type in my combination. Then I have about one minute to leave before the system is armed - enough time to exit and lock up. When I return and open the door, the control panel beeps, signalling I have about one minute to enter my combination before the security company is alerted. It really is pretty simple.
As for the show, I'm taking a break and not watching it for a while. It is interesting, but is also the kind of show where after viewing 4 or 5 episodes, you'll get pretty much all the info you need. Unless of course you just love to watch homes getting burgled!