The formation of a diversity of structures via the assembly of colloidal particles is hindered by the paucity of available particles, the difficulty of attaining monodisperse samples, and the lack of tunable and selective interactions. We will present the development of a controlled colloidal system based on photolithographically-designed particles of well-defined size and non-spherical shape. We will discuss the fabrication and characterization of these particles and the formation of controlled dispersions. With state diagrams (see figure - volume fraction of depletant vs. ionic strength) we will elucidate the role of DLVO and depletion interactions in defining a diversity of assemblies. Finally, we will present comparisons to theory and comment on the influence of surface roughness and steric stabilization in controlling the observed phenomena.