ATI X1950Pro Video card ($160 AR)
AMD Opteron 165 Overclockable ON AIR on stock HS/Fan to 2.7-3GHz ($150) Also has 1MB cache each core.
Any NF4 motherboard ($80)
Decent RAM for fast FSB speeds, like about 7GB/s RAM transfer rates ($140 or so)
2 250GB SATA 2.0 drives striped for fast access times ($140)
G5 Mouse ($45)
any Keyboard ($10-$30)
Decent PSU ($50)
Some random case ($40)
NEC DVD-R ($30)
$845-$865
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If you need a monitor go with a cheaper keyboard, drop one of the drives and get cheaper RAM (about $80 less) and buy the Sceptre 20.1" WSXGA+ LCD Monitor that's on sale right now.
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Have more money? Get an Intel chip (Intel is the fastest right now if you have the money to spend) and get a better video card 8800GTX sounds good right now
Oh and yeah... tigerdirect blows go with newegg.
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