Doorbell:
https://ring.com/
It is not perfect. BUT, it works as advertised, and I have had it running for a few months now without a problem. (unpacked it, connected it to my computer to update firmware, removed my old doorbell, and mounted this over it using existing doorbell transformer.
DVR System:
http://nightowlsp.com/
I have had this running for over a year. I have an 8 channel wired DVR system. I am going to get another 16 channel one to add more cameras for inside and more for a layer of coverage further out (walkways and streets, etc).
Note: With the DVR system you have to learn/know how to forward ports on your home router so you can see your cameras from outside your home network. Night Owl provides a DDNS service so you do not have to know what your home public IP address is.