same old stuff really not much changed aside from a bus speed here and there. look at tomshardware for reviews and comparisons of parts to get the best set.
As a basic spec, you want intel dual core, you want a p35 chipset motherboaard, you want something with SLi compatible PCI express ports in there...i'd recommend two in case you wanna upgrade later, you want 1066 speed ram oh if you get a decent g card, make sure it's HDCP (i know you know that), look for HDMI out if thats important...