Colloid–polymer mixtures exhibit a very interesting phase behaviour. Mixtures form gels, show gas–liquid coexistence, or display colloidal (liquid) crystalline phases because of depletion effects. In some cases even three or four-phases coexist simultaneously. In model studies where this phase behaviour has been studied, rather idealised systems are considered. We plan to extend current understanding towards more complex mixtures where charges are present, polymers are more realistic, polydispersity effects are taken into account, and soft interactions occur, as to better understand current and future applications.