Hope you don't mind me pasting it here, but some people are tolazy, even to click a link.
Motherboard
DFI "LANPARTY UT nF3 250Gb" NVIDIA nForce3 250GB Chipset Motherboard For AMD Socket 754 CPU -RETAIL($103)
Case:
Rosewill Value Series Black ATX Mid-Tower Super Case with 350W Power Supply, Model "R103A" -RETAIL($30)
PSU:
DYNAPOWER 430W P4 Ready Power Supply (Black), Model "DP-43XB.W2254" -RETAIL($35)
CPU:
AMD Athlon 64 3000+, 512KB L2 Cache 64-bit Processor - Retail($150)
HDD:
Hitachi 80GB 7200RPM SATA Hard Drive($63)
RAM:
Corsair Value Select 184 Pin 512MB DDR PC-3200 - Retail($75)
DVD RW+-:
Samsung 12X DVD±RW, Model TS-H542A/WBCH Black, OEM(55)
Video Card:
ATI Radeon 9700 PRO 128MB VGA DVI TV Video Card($150-eBay)
Keyboard:
Microsoft MULTIMEDIA KEYBOARD Special Edition PS/2 102 keys -RETAIL(20)
Mouse:
Microsoft Optical Wheel Mouse BLACK PS/2 /USB Version 1.1a -OEM(15)
Monitor:
MAG InnoVision 772PFb 17" Pure Flat CRT Monitor RETAIL($109)
Operating System:Windows XP($100)
Total - $865
One thing I recommend a better case/PSU. Antec makes some great cases/PSU's. I am sure some are close to the range you are looking to spend. Also I am not 100% sure, but you may be able to find a better deal on a video card. 150.00 seems a bit high for a 9700Pro. I thought I had seen used 9800Pros for like 160.00, but I may be wrong.