In reply to An Triubhas:
Softshells with a membrane like Powershield or Windstopper don't work so well under hardshells because you end up with two significant barriers to moisture movement (the waterproof membrane and the softshell membrane). If the softshell doesn't have a membrane, the combination will be more breathable, although perhaps less so than with a fleece and a hardshell.
If you're moving, then I'd take off the softshell, as it would get too hot but if you're stationary then the breathability would be less of an issue.