This paper reviews results obtained from low temperature scanning tunneling spectroscopy investigations on cleaved 2H-Nb1-xTaxSe2 and Bi2Sr2CaCu208 single crystals. Our study of the former crystals allowed us to image the vortex lattice, and to study how the peak in the density of states in the centre of the vortices is modified by the transition from the clean to the dirty limit. We have also been able to observe slow vortex motion with this technique. In our study of the Bi2Sr2CaCu208 compound, we have been able to obtain reproducible I-V characteristics while scanning. The characteristic features of the differential conductance spectra are sharp peaks at the superconducting gap edge, a weak dip beyond this energy at negative bias, and a finite conductance below the gap. The gap is found to have a value of 31±4 meV, but the experimental density of states shows the presence of states below the gap and cannot easily be fitted to a BCS like s-wave state.