Nick, this is a topic that has far too many contradictions and I'm far from happy with the advice I have to give. The with or without a vapor barrier starts with, does local code require one. That trumps all advice. If not required, then is this new or old construction. if new then there will be less accumulation of dust and other food sources for any mold. If an existing foundation then one need to wonder whether mold spores and food will decide to start growing in a moist environment. With a vapor barrier the inside surface of the foundation will slowly accumulate moisture until it matches the outside. I've seen what can grow behind a vapor barrier so my best advice is to omit it when you are allowed to and control the small amount of moisture that does dry to the inside.
The use of rigid against the foundation has the added advantage of keeping the inside surface that any air can reach above the dew point and it slows any moisture movement as it is a vapor retarder. If you were to use just a vapor barrier against the foundation and then fiberglass insulation, then humid basement air that leaks into the wall assembly will be able to find a surface cold enough to form condensation.
Open for suggestions.