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We study the polarized Electronic Raman Scattering (ERS) of several classes of high-Tc cuprates as functions of temperature, doping, and pressure with an emphasis on the effect of superconductivity. The doping dependence of the single-layer HgBa2CuO4+δ (Hg1201) confirms our earlier observations from two-layer Bi2Sr2CaCu2O8+δ (Bi2212) that the superconducting energy gap is highly anisotropic at optimal doping, but that 2Δ peaks associated with superconductivity are not present in underdoped crystals. Low temperature ERS measurements of the n-type (T′) Pr1.85Ce0.15CuO4 at optimal doping (Tc = 20K) show negligible gap anisotropy, consistent with other spectroscopic results which suggested an isotropic s-wave order parameter. Normal state Raman scattering measurements of underdoped Bi2212 at pressures up to 7.6 GPa reveal anomalies in the lattice dynamics which offer insight into local oxygen ordering and may influence the observed large hysteresis in Tc(P).