Based on test scores I would say
Kennesaw- Lost Mountain
I recommend researching the following sites: The Georgia report card http://www.gppf.org/default.asp?pt=doc&doc=reportcard
and the National center for educational statistics:
*Be careful what you select in the suburbs of Atlanta, schools are what drive property values.
As a parent myself, I also recommend that you visit the school so you feel comfortable with the administration at that particular school.
Being an native of the area, if you have any further questions, just give us a call, Both Heather and I went through the Cobb County school system and are now embarking on our children starting school.
The Shroyer Team- Brian & Heather 678.851.5558 http://www.atlantahomespot.com