Yes, that would be great, for a 64bit application, but WoW runs in a 32bit environment withing Vist64, which still can only utilize 4gb total.

To test this at home (you Vista64, 8gb ram users) go disable your pagefile.sys, open your hardware monitor, then try to multibox. As things start to load, your total ram usage will increase, then bluescreen due to lack of memory, long long before 8gb are ever used.

WoW will be a problem, graphic design with newer software will be great.