Get a security light with two bulb fixtures, screw in a two outlet adapter on one side, screw in the bulbs, plug an alarm into one of the outlets on the adapter.
Get a security ip camera that will alarm and send you emails with video captures when video motion is detected. Then when you get the email notification you can then log in a view the camera video in real-time. My cameras has 2-way audio also so I can hear and speak through the camera. My camera also has night vision and I can control the camera viewing position. I also have motion flood lights on all corners of the house and on my deck. An intruder might be able to disable the camera but not until they first activate the alarm and video/picture capture that's sent to you via email. You can be notified no matter where you are via smart phone.
I've been using a pair of Amcrest IP2M-841 IP wireless IP cameras for the better part of a year. The video is pretty sharp both day and night, they have the ability to send photos and videos over the internet, and to send notification emails when they sense motion. I don't use those features, preferring instead to do the same with a laptop that monitors all the cameras and other sensors, but the Amcrests are less than a hundred bux each and would give you a good start for not a lot of money. You'd have to mount them inside the house looking out a window or in some other sheltered location though, as they're not intended for outside use.
I also have a pair of Dahua IPC-HFW4300S cameras that are waterproof, and have them mounted under the eaves. They've also been very reliable, but each requires a wired Ethernet connection. Again, not very expensive and good bang for the buck.
The cameras are only supplements to a real security system that is monitored by ADT. I don't think the camera based technology is reliable enough yet to trust with calling the police, but it is good enough to confirm an alarm signal, use for checking up on things when traveling, or provide images to help identify someone that came onto the property without my permission. Or even someone that pokes around, perhaps where they shouldn't be, when they've been invited over.