We present an analysis of the large-scale structure of the halo of the Andromeda galaxy, based on the Pan-Andromeda Archeological Survey (PAndAS), currently the most complete map of resolved stellar populations in any galactic halo. We divide the sample into stream-like populations and a smooth halo component (defined as the population that cannot be resolved into spatially distinct substructures with PAndAS). Fitting a three-dimensional halo model reveals that the most metal-poor populations (Fe/H < -1.7) are distributed approximately spherically (slightly prolate with ellipticity c/a - 1.09 + or - 0.03), with only a relatively small fraction residing in discernible stream-like structures (f sub(stream) = 42%). The sphericity of the ancient smooth component strongly hints that the dark matter halo is also approximately spherical. While qualitatively in line with expectations from cosmological simulations, these observations are of great importance as they provide a prototype template that such simulations must now be able to reproduce in quantitative detail.