The influence of transversal density nonuniformity on the propagation of electromagnetic surface waves along plasma slabs and columns in the presence of collisions is analysed and illustrated by numerical evaluations for phase diagrams of axially homogeneous plasmas. Moreover, the changes in dispersion and damping caused by the occurence of plasma resonances in the transversal/radial density profile are studied. In addition, complex modes and backward waves in the collisionless dispersion curves of isotropic plasmas are treated.