Poser 6 and 7 on Vista 64 bit, no issues at all!
I can't understand anyone going for 32 bit if they're buying new, 32 bit is dead, 64 is the way to go, all major manufacturers now have 64 bit drivers, there's no reason in the World not to go 64 bit and every reason why you should!

Injustice will be avenged.
Cofiwch Dryweryn.