In this work a simple concept was used for a systematic search for new materials with high spin polarization. It is based on two semi-empirical models. Firstly, the Slater-Pauling rule was used for estimation of the magnetic moment. This model is well supported by electronic structure calculations. The second model was found particularly for Co2 based Heusler compounds when comparing their magnetic properties. It turned out that these compounds exhibit seemingly a linear dependence of the Curie temperature as function of the magnetic moment. Stimulated by these models, Co2FeSi was revisited. The measurements revealed that it is, currently, the material with the highest magnetic moment (6 muB) and Curie-temperature (1100 K) in the classes of Heusler compounds as well as half-metallic ferromagnets.