It depends on how much you wish to spend. I had an Aver media setup for years and thought it was good quality; until I saw the Comelit setup. As in most things in life, you get what you pay for. Although saying that, the Comelit are excellent value.
Yes, you can buy a system off eBay for half the price, but you end up with less than half the quality and if as you say, you want it to ID the little darlings, you need quality. You can also buy HD zoom cams to pick up faces in detail as they enter your property. Not the Pan, tilt & zoom type, just an HD cam with a manual zoom & focus control that you set and leave.
On my system I can clearly read a car registration from 60-70 meters away. Most modern cameras nowadays come with IR fitted, The night vision is spectacular, it automatically drops the camera into B&W under low light levels to improve picture quality. The only way around that is to fit an automatic flood light, then you can see what colour clothes they wear. (Then that way you can provide them with some light so they can grind their weed in comfort).
You can hook the whole system up to your internet and watch your home from anywhere in the world using the internet and a smartphone app.
If you decide to go down the cctv
route you'll need the DVR, some Cameras, a power supply for the Cams and cabling. (I think they sell "Shotgun" cables). these are pre-made and save you having to put the connectors on the wires. If you're going to use your TV as a Monitor, you'll need an HDMI cable to connect the DVR to the telly. If you want a dedicated monitor ask the guy in the shop about which cables you'll need to connect to it.
Hope that helps
Be warned, once you go down the cctv
road it can get addictive.