Uzzah. Sorry to hear of this. I used to work in the electronic security field 18 years ago, and your reaction was very typical of most I came into contact with. Very upsetiing that some stranger bastard has rumaged through your drawers, cupboards and personal spaces, not to mention some of the terrible damage and vandalism I've seen.
I installed a security system in our new house, when we moved in 7 years ago, and since then I have had 2 attempts, that were thwarted due to the fact that I had a system, and it was triggered, when they attempted to pry open basement windows.
In both cases, it was in daylight hours, during a school week. Most of these type of break ins are perpetrated by young teens who should be in school, looking for a quick buck, or merchandise to fence. They are usually in and out of the house in under 5 minutes. 2 punks inside, 1 outside as a lookout.
If any one is considering a security system, be certain to price one out, that includes perimeter sensors, on all basement and ground level windows and doors. This will allow you to "arm" it even while you are home. And if you can afford it, pay for the monthly monitoring. Many Alarm companies will offer to monitor additional alarm codes such as fire, low temperature, water etc, for the same monthly fee, or slightly more.
P.S. Deal with a reputable Alarm Company in your area, whose Alarm stickers are recognized and respected. Stickers from the "buck or two" store are a joke.