I am in Murphy (East of Plano, North of Richardson, South of Allen, West of Sachse/Wylie) and we love it here. Small town feel, great neighbors, and they do a lot of family friendly things both in the town and in our neighborhood.
We moved here from Northeast Richardson (Renner/Northstar Road) and we loved it there as well, we just couldn't afford that area as easily as we could the house we found in Murphy.
The people here seem to have a pretty good relationship with the police department and the neighbors watch out for each other which helps with crime. That's a huge reason we will be living here for a long time to come.
You asked how to check for good places and one idea comes to mind which is what I used to narrow down where I wanted to live:
On Century21's website, they had a tool on there that allows you to check crime statistics for a prospective neighborhood. That is usually based off of the police activity reports logged in the area.