I just bought the following items from Newegg about 2 months ago for $1324 ($1439 including tax and shipping):
Microsoft Windows Vista Home Premium SP1 64-bit DVD - OEM
OCZ Platinum 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory Model OCZ2P10664GK - Retail
Intel Core 2 Quad Q9300 Yorkfield 2.5GHz LGA 775 95W Quad-Core Processor Model BX80580Q9300 - Retail
ASUS P5Q Deluxe LGA 775 Intel P45 Intel Motherboard - Retail
Western Digital Caviar SE16 WD5000AAKS 500GB 7200 RPM SATA 3.0Gb/s Hard Drive - OEM
Antec NeoPower 650 650W ATX12V / EPS12V Power Supply - Retail
MSI R4850-T2D512 Radeon HD 4850 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Retail  
SAMSUNG 2253BW Black 22" 2ms(GTG) DVI Widescreen LCD Monitor - Retail

Take out the Windows Vista ($99.99), monitor ($269.99), and power supply ($99.99...if yours is powerful enough) and you are looking at  a grand total of $854.. But you may need to add $70-$150 for a new case.