This paper examines the calculation of some equilibrium properties of colloidal dispersions from liquid state theory. Starting from a simple model of sterically stabilized dispersions viewed as binary mixture with large solute/”solvent” size ratio, we first analyze the solvent mediated potential of mean force between the colloids computed from integral equations and density functional theories. The associated phase diagram is next computed in the effective one component fluid approach. The emphasis is put on the modification with respect to hard sphere mixtures produced by short range attractive forces. The subtle competition between solvent-solvent and solute-solvent interactions is emphasized in a situation appropriate to solute/ molecular solvent mixtures. The relevance of the concept of ” hard sphere- like” colloids is finally challenged starting from an example showing the profound effect of residual non hard core interactions on the phase diagram of pseudo- binary mixtures.