The possibility of light manipulation at the nanoscale relies on the efficient coupling of the electromagnetic waves to surface excitations such as surface plasmon polaritons (SPPs). We expand on the work by Pendry, who put forward the idea of spoof surface plasmons in conducting films as a way to engineer SPP dispersion curves. We find that the surface texture and geometry can play an important role in determining the dispersion. We then compare the specific cases of circular versus rectangular textured surfaces and observe that the plasmon modes are less tightly bound in the former case. This dependence on geometry can also be used as a means for defect engineering or fine-tuning the regular plasmon dispersion.