I love clang's library (libc++). It was written from scratch, directly to implement C++11, so a lot of code in it actually makes sense to me (but then there's an occasional BSDism, as in transform_primary())
Or if something else, what do you use?
Professionally, I use the compilers that are provided and supported by the hardware vendors: IBM xlC on IBM, Sun (Oracle) Studio on Sun, HP aCC on HP Itanium servers.
For the hobbies, it's Intel C++ (they have many great libraries, and perform better than GCC in a lot of cases), Clang++ (for the language and library support), and GCC (for the lowest common denominator)