  We calculate the stability diagram for a trapped normal Fermi or Bose gas
with dipole-dipole interactions. Our study characterizes the roles of trap
geometry and temperature on the stability using Hartree-Fock theory. We find
that exchange appreciably reduces stability, and that, for bosons, the double
instability feature in oblate trapping geometries predicted previously is still
predicted by the Hartree-Fock theory. Our results are relevant to current
experiments with polar molecules and will be useful in developing strategies to
obtain a polar molecule Bose-Einstein condensate or degenerate Fermi gas.
