Quadro FX4600 768MB 384-bit GDDR3 PCI Express x16 HDCP Ready SLI Supported Workstation Video Card best card you will ever lay eyes on! works wonderfully under workstation loads.

-OR-
NVIDIA Geforce 9800(4-way sli)
though its not a card meant for rendering( its meant for gaming) it can do the job. just not as effeciently.


3-4 gigs of ram.
if i were you id upgrade to an sli motherboard and get two of the fx4600's
(thats if you have the dough)

dual-core processor(or if your just insane quad cores are always nice)
1Tb hard drive(SATA)
cd/dvd/lightscribe combo(SATA)
a physX card(the choice is yours on the physx cards...)
a nice heatsink(with fan) to keep the pc cool.
oh and fans(GOOD fans)
- liquid cooling solutions is an option but make sure you know what your doing

750watt powersupply(or 1000 if your still insane)
2 monitors(or 4 with the quadro fx4600)
HDMI connections

latest pixel/vertex shader( i think is 3.0 or 4.0)

and ofcourse a cool looking case with a clear side panel to let the world know "yea...my pc is bad a$$" and put some LED fans inside the case(green!!!) and let your freshly built beast ROAR! " I AM THE BIG GREEN BEAST BRED FOR RENDERING!"