If you are looking for a private secular school, Fort Worth Country Day School http://www.fwcds.org/public.shtml and archrival Trinity Valley School http://www.trinityvalleyschool.org are VERY close, VERY good and VERY highly thought of.
I went to public schools and private schools and ended up graduating from FW Country Day. It sure made college MUCH, MUCH easier! In fact, I didn't appreciate FWCDS nearly as much until I went to college.
It states that: "Twenty-nine percent of the [FWCDS] Class of 2002 earned recognition in The National Merit Programs. This class includes two of the states 28 Semi-finalists in the Presidential Scholars Program. The average SAT of this exceptional class is 1300. Twenty percent of the class earned one or more top scores of 800 in a section of the SAT or SAT II Achievement Tests or a top score in one or more sections of the PSAT, totaling 27 perfect scores."
WOW!!! I'm impressed!