A lot depends on what graphics programs you want to run. I'm very happy with my Intel Q6600 quad core setup, runs Poser 7 and Vue 6 Infinite like a dream, and 3DS Max ain't sloppy either.

Here's what I'd recommend (quite some $$, I'm afraid):

CPU: Intel Q6600 quad core.
RAM: 4x2 GB DDR2-667 (which brand isn't important, fast and expensive memory will only get you a 1% performance "boost").
Mainboard: Intel P965 based (either an Intel or an MSI mainboard). Comes with at least 4 SATAII connectors, supports Intel Matrix RAID, plus 1 IDE connector for optical drives.
Graphics: if you're using Max or Maya I can highly recommend a 3DLabs Wildcat Realizm 200 (around $650). A professional 3D graphics card, VERY good with geometry (outperforms any ATI or nVidia professional graphics card cheaper than $2000). Great OpenGL support -  but I don't know how it supports XP 64 bit.
If it's to expensive, I'd recommend an nVidia 7900 series graphics card. Those are hard to come by, nVidia is phasing them out in favor of the 8000 series, but the 7900GS is fast and affordable, while the 7950GTX is extremely fast (and more expensive, around $400). Not as fast as the 3DLabs though.
Harddisk: Seagate Barracuda 7200.10 SATA II disk, 320 GB (preferably 2x)
Case: Chieftecs are good.
Power supply: Enermax is a good brand, but 430 W is a little low. I'd suggest a Zalman HP-600, quiet, 600 W, detachable cables.
Operating system: Windows XP Pro 64 bit. Every decently programmend 32-bit app runs fine on XP 64 bit, nVidia has good drivers for their graphics cards, and it's rock solid - based on Windows 2003 Server 64 bit.

The pen is mightier than the sword. But if you literally want to have some impact, use a typewriter

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