As McKinney continues to grow, the surrounding suburbs will too. Presently much of the growth is to the South, as many Collin County residents commute to Dallas for work. However, McKinney has plans to expand which will allow businesses to move North too, allowing more development to be supported in that direction.
Currently Melissa, TX is a community that is actually promoting growth in their area. You may have seen their advertisments touting it as "easy to find, hard to leave". Keeping all of these things in mind, it would probably be a good real estate decision to purchase there if it suits your families needs (location, size, etc) as you can get a better price in Melissa as opposed to an area further South (like Fairview or Lucas).
The Country Ridge neighborhood specifically, was built in 5 phases. All of those homes have a minimum 1-acre lot which makes them more desirable to some people. Currently there are 14 homes for sale in that neighborhood with prices ranging from $299k-$700k. Of the homes that have sold there recently, the prices range from $287k-$497k. As you can see, the lower priced homes are the ones with some activity right now. The currently economy and mortgage industry news is likely holding some people back from purchasing the more expensive homes.
If you and your family are considering purchasing a home similar to these in Melissa, I would recommend making a comparison to other similar properties throughout Collin County. There are virtually no other homes for sale in Melissa that compare to this special neighborhood; however there neighborhoods like this in other surrounding cities.
Please let me know if you are interested in the other comparable neighborhood information. I would be happy to provide any additional information you may need to make an informed decision.