By providing a plurality of support brackets which are quickly and easily mounted to any desired surface and are constructed for receiving and supportingly retaining elongated, lineal crown molding strips, inside and outside corner seam covers, and lineal seam covers, each of which are formed from a wide variety of decorative and visually distinctive appearances, a cornice or crown molding system is achieved which is capable of being quickly and easily installed in any desired location by any unskilled individual, without requiring the use of mitered corners, abutting junctures, nails, adhesives, and the like. By employing a combination of the components of the present invention, any desired location can be quickly and easily decorated with a completely installed molding system for enhancing the visual and aesthetic appeal of any room or building.