Dogs are regularly the top of the list. Trained dogs know not to take food from unauthorized people. We have 2 Rottweilers & a 140lb Rottweiler/Lab, and they have a command that they hear before they will accept food. They roam the house freely at night (& day). To poison them, an intruder would have to break in first, and that's not going to happen without the dogs singing the "someone's near the house, mom" song (
http://melissamarr.tumblr.com/post/19351362993/two-out-of-three-of-my-canine-alarm-clocks).
Likewise, in a lot of places the power box that one would need to access to disable the security systems (glass-break sensors, motion detectors, sensors on windows & doors) is inside the house. That security system sends signal to an office. You can also set that system on a unique power source OR run a backup power source (which is also handy to have in general).
At my writing cabin, I also have motion-activated flood lights which are practical for energy conservation and security.
I'm very security conscious after a few experiences earlier in my life and experiences friends have had. Two different friends (one in Durham NC & one in Pittsburgh) had their homes entered during grad school. One was an armed invasion; one was just a knife. Both were mid-day doors unlocked. I had a stalker in my 20s. The first thing I learned--that people often fail to keep in mind--was to lock the doors & ground floor windows when you're home too. Obviously, that varies some depending on where you live, but sometimes the best defense is simple, common sense. When I moved to a new place, I keep the street-facing curtains down initially so the big dogs are very visible. I walk them at high visibility times. If anyone came to the door, I invite my dogs to speak. Marine Corps flags are handy too. An NRA sticker doesn't hurt. To an intrusion minded person selecting a target, those are all clues as to which houses are easiest.
A house in my neighborhood was robbed two years ago. It was one of the few here that had a) no dogs & b) no alarm. The intruder cut the glass to the side of the door, reached through & turned the bolt. The following week, we replaced our bolt with a key-only lock. Little fix.
I'm sure that all of the above can still be overcome by pros, but unless there is something the intruder really wants in a particular house AND is skilled AND did research on the target, the house should be secure. Trained big dogs are the top pick though. (A trained Marine in the house is handy too, but they are a little more complicated to acquire & keep
)