diff -up VTK/CMakeLists.txt.system VTK/CMakeLists.txt
--- VTK/CMakeLists.txt.system	2010-09-27 14:40:00.000000000 -0600
+++ VTK/CMakeLists.txt	2011-02-08 14:08:29.367122550 -0700
@@ -106,6 +106,11 @@ IF(CMAKE_CONFIGURATION_TYPES)
 ENDIF(CMAKE_CONFIGURATION_TYPES)
 
 #-----------------------------------------------------------------------------
+# Do we try to use system libraries by default?
+OPTION(VTK_USE_SYSTEM_LIBRARIES "Use the system's libraries by default." OFF)
+MARK_AS_ADVANCED(VTK_USE_SYSTEM_LIBRARIES)
+
+#-----------------------------------------------------------------------------
 # Load some macros.
 INCLUDE(vtkDependentOption)
 INCLUDE(vtkThirdParty)
diff -up VTK/CMake/vtkThirdParty.cmake.system VTK/CMake/vtkThirdParty.cmake
--- VTK/CMake/vtkThirdParty.cmake.system	2010-09-27 14:40:00.000000000 -0600
+++ VTK/CMake/vtkThirdParty.cmake	2011-02-08 14:07:46.424662568 -0700
@@ -1,6 +1,6 @@
 #-----------------------------------------------------------------------------
 MACRO(VTK_THIRD_PARTY_OPTION upper lower)
-  OPTION(VTK_USE_SYSTEM_${upper} "Use the system's ${lower} library." OFF)
+  OPTION(VTK_USE_SYSTEM_${upper} "Use the system's ${lower} library." ${VTK_USE_SYSTEM_LIBRARIES})
   MARK_AS_ADVANCED(VTK_USE_SYSTEM_${upper})
   IF(VTK_USE_SYSTEM_${upper})
     IF(EXISTS ${CMAKE_ROOT}/Modules/Find${upper}.cmake)