Recommendations for a usable, fast C++ matrix library?

Does anyone have recommendations on a usable, fast C++ matrix library? What I mean by usable is the following: Matrix objects have an intuitive interface (ex.: I can use rows and columns while indexing) I can do anything with the matrix class that I can do with LAPACK and BLAS Easy to learn and use API Relatively painless to install in Linux (I use Ubuntu 11.04 right now) To me, usability is more