I have a SimpliSafe system without the monitoring. No monthly fees.
This is definitely an option, but I always like to stress the idea of layered security. I don't think that you were suggesting only buying this one product, but I just want to clarify. You want to get good locks, strengthen the door and lock hardware, add a bit of window protection, maybe even a gate/fence/wall. After you take care of the physical security, then you can start getting into the electronics. Things like cameras, motion sensor lights, and alarms (monitored or otherwise) are additional precautions. You really want a baseline of defense. The issue with any of this stuff is that it can get a little expensive. The cheapest stuff is going to be the physical security. Locks can get pretty expensive, but they are one of the first lines of defense. More than picking resistance, you don't want a lock that can be bypassed or forced open. That means you need to get something that is quality made with strong metal.
Hard metal, and a lot of it, is going to protect you against people just trying to kick in the door. In most cases, one well-placed mule kick will open any door. That is why you also need the door itself to be secured. Because a door needs holes drilled in it in order to have locks installed, the door is going to be made weaker. Invest in a product like a door devil, or something like it, and secure the hinges, hardware installation holes, and strike plate (three weak points on a door). Windows are glass, so there is not a lot you can do, but there are security films that you can buy. This will not make your windows unbreakable, but they will sure put up a fight. Again, this stuff can get a little expensive, so I would recommend doing a risk assessment. Follow these instructions, and you should be able to figure out exactly what the best investment is going to be:
http://united-locksmith.net/blog/is-your-home-safe-how-to-assess-your-home-security-like-a-professionalOnce you know what you need, just be sure that you reassess your security ever so often. The article gives a pretty short time frame. I would say use your best discretion. There is no need to redo your security unless something dramatic happens in your area.
Good Luck!