Sony HVR-Z1U or the PD-170 ?

Depends on what your shoot conditions are. PD-170 has far better low light performance. Shooting in HDV may give you doc better market longevity as things eventually move to HD. Als HDV doesn't not handle fast mostion well (it softents) so this may impact your work if you shoot things like trees blowing in the wind, fast moving animals, action sports for example. There's also added time and or cost of an HDV workflow to consider. Of course the FX1/Z1 does greate 16:9 DV but keep in mind the low light restrictions.