Foo is right on the money!
Def. a dual core+ cpu
If you can swing it, get two SLI GPU's
and the most RAM you can fit/swing never hurts.
I'm running a custom built AMD 64FX dual Core overclocked to 2.73gz on a ASUS A8N32-SLI Deluxe mobo with 2GB of RAM and 3 x 400GB Seagate 7200rpm SATA HD's.
Make sure you also get a big enough power supply to provide for all these 'power hungry' components as well as plenty of cooling fans, front and back.
You can check alienware and falcon-nw for what's hot in cutting edge components and then order them via newegg or others ( if you are into building your own pc's )
cheers
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