  Critical effects at complete and critical wetting in three dimensions are
studied using a coupled effective Hamiltonian H[s(y),\ell]. The model is
constructed via a novel variational principle which ensures that the choice of
collective coordinate s(y) near the wall is optimal. We highlight the
importance of a new wetting parameter \Omega(T) which has a strong influence on
critical properties and allows the status of long-standing Monte-Carlo
simulation controversies to be re-examined.
