We present a unified analysis of single excitation vector models in three dimensions. We show that there is a family of first-order master actions related by duality transformations which interpolate between the different models. We use a Hamiltonian (2+1) analysis to show the equivalence of the self-dual and topologically massive models with a covariant nonlocal model which propagates also a single massive excitation. It is shown how the nonlocal terms appears naturally in the path integral framework.