About a cheaper x64 program for CG i think that Vue have had it since 2007, and they support multiple cores as well.
In vue its much more needed than in poser tho, a scene with a couple of billion polygons tend to eat memory and the 2gb limit in 32 bit doesnt really help with that :P
I agree that it is good poser is getting it tho, since poser figures tend to be very poly and texture heavy large amounts of ram can only be a good thing.
I also belive that aplications such as maya/max/lw etc tend to use "smarter" soltions requiring less memory (sub d) and i think the textures usually are a lot lower res unless its in extreme closeups.
In poser there is the "1 size fits all" thing going and therefor it tends to be very large texture maps and rather extreme polycounts involved.
A step in the right direction, but it will require a lot more before i use poser to actually render anything tho.