My test was on 32-bit Vista.
I don't have a single 64-bit application, so I think it's premature for that.

As for Open GL, I did try loading Daz|Studio both from within Bryce and stand-alone and that does load Open GL according to the initialization messages. Other than the fact that I have no content loaded (it is a work machine after all), it seemed to work fine.

On a related question, the laptop is a Centrino Duo, and Bryce seems to render with both cores.  Has anyone tried it on a real dual or quad core system to see if it uses the full horsepower to render?