This is a really great thread bagginsbill, very useful for people trying to get more realism into their Poser renders.
When I used to render in Poser I always used AO as it greatly enhanced the realism, which you have shown & explained really well here. After using AO, renders done without it just look bland.
I've been a Vue user for some time now as GR, GI & AO are incorporated into the software with great effect. I think Poser users would get even more from the software if EF would put Global Radiosity into their next program. I've heard it can be faked in Poser, but I've never tried it.