Stable clean and hydrogenated diamond (100) and (111) surface reconstructions found by density-functional molecular-dynamics (DF-MD) are characterized in their vibrational and electronic properties. For sufficiently large surface slab supercells we plot spatially resolved charge densities of the highest occupied surface states at constant height, which are compared with recently obtained images from scanning tunnelling microscopy. In addition, we have calculated the surface top-three-layer projected vibrational spectra and reproduce the main features obtained from experiments. The various reconstructions of the diamond surface yield rich spectra of surface modes involving excitations of dimers, trimers and chains. We classify most characteristic surface modes and discuss correlations to peaks observed in surface-sensitive experiments. Both calculated charge density distributions and vibrational spectra represent signatures of the considered surfaces that might be used to understand and to classify as grown diamond surfaces.