Thank you everyone.
Ray, Apple can ship with any one of these two cards. Sounds like one of this will work just fine--from the discussion above.
NVIDIA GeForce GT 120 with 512MB of GDDR3 memory, PCI Express 2.0, one Mini DisplayPort, and one dual-link DVI port
ATI Radeon HD 4870 with 512MB of GDDR5 memory, PCI Express 2.0, one Mini DisplayPort, and one dual-link DVI port
Talking about the processor cores, will VW take advantage of 8 core or that will be an overkill too? I know one can never go wrong with extra memory if ones budget allows.