We review the structural, electronic and dielectric properties of atomistic models of the Si(100)-SiO2 interface, which have been purposely designed in order to match a large variety of atomic-scale experimental data. After describing the generation procedure and the structural properties of two specific interface models, we study the corresponding electronic structure and dielectric response within the framework of density-functional theory. Particular emphasis is given to a systematic comparison between the atormstic properties of our model interfaces and experiment. Besides. synthesizing the present status of our experimental knowledge on the Si(100)-SiO2 interface, these models provide a solid and necessary basis for future investigations in the area of gate stacks for Si-based microelectronics.