A unified theory is presented that describes the thermodynamic and dielectric properties of the electron liquid throughout the full range of thermal degeneracy: from the zero-temperature fully degenerate Fermi plasma to the high-temperature classical one-component plasma. Through an approximate inclusion of local-field corrections in the polarizability, results are obtained that are accurate up to intermediate values of the coupling strength. For future applications, closed-form parametrizations are presented for the thermodynamic and dielectric functions, as functions of density and temperature. The consequences of an increase in temperature on the plasmon dispersion and damping, on the energy-loss function, and on the pair-correlation function are also studied. We find that quantum effects can be observed in the short-range behavior of the pair-correlation function even for some plasmas that are conventionally classified as classical.