The peculiar catalytic activity of Au-supported titanium dioxide surfaces in the CO oxidation reaction has been a focus of interest for more than twenty years. Herein, recent data concerning preparation and structural characterisation of planar catalyst model systems consisting of single-crystalline titania and/or gold nanoparticles deposited thereon is presented and reviewed. We first expand on the deposition and growth of TiO(2) films on selected metal host surfaces and then consider the deposition of Au nanoparticles on these surfaces, including information on their geometric and electronic structures. The second issue is the interaction of these materials with carbon monoxide (one of the essential ingredients of the CO oxidation reaction) which serves as a probe molecule and monitor of the chemical activity of the model catalyst samples. Concerted efforts relating the structural and chemical properties of the respective binary materials (titania support plus deposited gold) can help to tackle and finally resolve the still open problems concerning the high activity of Au-TiO(2) catalysts in the CO oxidation reaction.