Walnut Hill if your primary focus is performing arts. We have a friend who transferred there from PA and was launched very successfully from there.
George School has a very good program and lots of alums over the years who have ended up with theater careers. It is viewed as a serious part of an education, not as an EC. Worth a look.
One of the nice things about most prep school programs is that there is often a place for newbies and kids who want to participate but not star as well as for really talented, serious kids.
Kent School has some pretty famous alums in the entertainment industry. Seth McFarlane (Family Guy) has spoken about @ the theatre-drama program. I think Lana Del Ray went there and Alicia Coppola, Treat Williams and Ted Danson. When you visit the school, check out the theatre program.
Choate has a pretty strong theatre program and an Arts Concentration. Lots of talent attended or graduated from Choate: Edward Albee, Ali McGraw, Michael Douglas, Glenn Close, Paul Giamatti, Buck Henry, Bruce Dern, Jamie Lee Curtis and many important writers, producers, and directors whose names are not as popularly known. The Paul Mellon Arts Center was designed by I. M Pei and worth visiting:
