Tomcat and DJShymansky are both correct about Summerville HS (in Summerville) and Wando HS (in Mt. Pleasant). Both communities are wonderful for families with lower crime stats, good recreation departments, great shopping, etc. But here are a few differences to consider...
Summerville is about 45 minutes from the beach if there is no Sunday afternoon beach traffic and Mt. Pleasant is just minutes from the beach. Some neighborhoods are just a bike ride from Sullivans Island or the Isle of Palms.
Mrs. Lucy Beckham, the Principal at Wando, was voted the National High School Principal of the Year in 2009. http://www.ccsdschools.com/PressReleases/documents/LucyBeckhamPOY20090928.pdf (broken link)
Both schools are extremely large(over 3000 students), but very well respected academically. Wando is recognized nationally as a national top 100 High School.
Housing-wise, Summerville is less expensive. Farther from the historic district, farther from the beach, and farther from many of the lowcountry's best golf courses also mean more value in a home. Mt. Pleasant is more expensive, but has higher end restaurants, a better rec department (3 indoor municipal swimming pools) and nine golf courses located in the East of the Cooper area.
If schools are the top priority, I'd suggest giving each of their guidance depts a call and asking questions, talk to the coaches, and come visit us and arrange a tour of the schools. Nothing beats feet on the ground.
Some other schools to consider are West Ashley and James Island Charter High Schools
If you need more info, please contact me at 1.843.819.2467 and I'll send or e-mail you some relocation info.
Broker Associate, Landmark Enterprises Real Estate