No you shouldn't if you render any sort of animations directly from Poser. The 64 Bit version doesn't support as many video codecs as the 32 bit version does. In 32 bit you can render to DivX directly, but not in 64 bit because DivX doesn't do 64 bit yet. A lot of video codecs only work in 32 bit still.

And before everyone jumps in and says it's best to render images and put them together in some other program, Yeah yeah, whatever. Some of us want to render to AVI directly from Poser so this information is pertinant  to those of us who do.