  Within the Hubbard-Holstein model with long-range Coulomb forces, we revisit
the charge-ordering scenario for the superconducting cuprates and account for
the presence or the absence of a formed stripe phase in different classes of
cuprates. We also evaluate the mean-field and the fluctuation-corrected
critical lines for charge ordering and we relate them with the various
pseudogap crossover lines occurring in the cuprates and we discuss a mechanism
for their peculiar isotopic dependence. Considering the dynamical nature of the
charge-ordering transition, we explain the spread of T* and of its isotopic
shift, obtained with experimental probes with different characteristic time
scales.
