If money isn't a big deal, i would get the last high end CPU (quad core is enough), 3GHz at least, and video card (for SH probably an ATI 2Gb at least) and the more RAM as possible. Of course Win7 64 bit (Win8 isn't better).
This way you would be ready for anything coming out...(other games)
Anyway, after short time, all would be outdated
