I might get slated but maybe not I bought a system from eBay similar to this one http://www.ebay.co.uk/itm/Security-CCTV-System-8CH-720P-Surveillance-DVR-8X-1800TVL-24-IR-Outdoor-Cameras-/252625877108
You'll get 8 cameras which are easy to install, run the power/video cable to the DVR and plug in and then you are up and running.
You've got PC software to view the cameras while at home or away plus you've got iOS and Android applications available which you open up scan the QR code from your DVR or type in the number from the DVR into your smartphone and it'll connect up and you'll be live viewing without any messy portforwarding/firewall and dynamic DNS etc.
I've set the front door, back door and garage door which point in a way that motion should only occur if someone is going to be standing in view of the camera and I get email alerts with snapshots of who it is.
Hope this helps a little.
There are very very similar systems available as above available from SWANN but the price does jump a little.
Thermal - I've not heard of that really not in my price range.