The Quadro 4500 is what I've had put in the Precision, but from the point of view of the OP it doesn't make sense - unless you're reason for buying the machine is for 3D work, you're pissing away performance/$ with the Quadro for gaming. And this applies just as much to a Boot Camped Mac Pro as well as the Precision.
Oh I fully agree with you on that. The OP would not need the 4500 but for your needs it would have been the proper choice in the Mac Pro for an all in one solution instead of separately spending probably 12k or more on 3 seperate systems.
Tom