I have a system designed by a local company. The previous owners had installed a sytem, but it was past its prime, so I updated it when I moved in. I have all doors and windows in the house monitored, as well as fire sensors that dial into the fire station if they are set off. My control panels (one in my bedroom, one by the back door) have buttons for police, fire and hospital, and if I hit them they will send those services immediately, without waiting to call. If an alarm is set off, the monitoring company will call, and if they don't get an answer from a person including a password and number code, they will send the police.
Recently I also got a camera security system. I couldn't see who was at my front door, so I installed a camera at the corner of the house, behind the gutter. I could have 3 more, so 1 is on one side of the garage and looks down the driveway, another is on the opposite side of the garage and looks at my back door, and the last one is on the other side of the house and sees most of my back yard (which backs up to some woods.) I can see all four channels from my TV. It's the last thing I do before I go to bed at night - check and see that everything looks fine. If the front doorbell rings, I can see who's there and choose to answer or not. I don't have the system that would record those cameras, but I could add it if I wanted to, and I might sometime.
I feel much safer with this all in place.
Oh, I have a dog who barks loudly, too, although she would probably just lick a burglar if one ever got in the house!!