eh relack la. The Mac pro is a good choice and it can still run windows Just rmb the rams for mac pros are different from the standard ddr2 rams as many have pointed out. The graphic card u can buy multiples of them and use the ati crossfire interface to link them if im not mistaken.(not very sure. Dun own a mac pro.)
64 bit native windows os have been available for a long time if i dun recall wrongly. Tiger and leopard are native too. I dun really see the difference to warrant the arguments.