I've let renders go overnight, if not longer.  The first image in my gallery took 23 hours because I'd turned on AO and had a mirror, which just drove Firefly nuts.  Still I was very pleased with how that came out, so I don't mind letting this one run its course.  (Work's been a bitch lately anyways, so it's not I've got a ton of time to play with Poser... not like some people I know who can play with Poser at work ;-)

What driving me nuts, though, P6's fool memory limit.  I had to dump a bunch of stuff from it because it ate up too much memory, even with smaller buckets and smaller/fewer textures.