Want to build a gaming system. Are the parts below fully compatible and have I made good choices on quality of ingredients?
Antec CP-850 850W Continuous Power Power Supply
Antec Twelve Hundred Black Computer Case With Side Panel Window
Intel Core 2 Quad Q9550 2.83GHz LGA 775 95W Quad-Core Processor
SAPPHIRE Radeon HD 4870 X2 100251SR Video Card
Western Digital Caviar Black 640GB 3.5" SATA 3.0Gb/s Hard Drive
Scythe SCORC-1000 140mm CPU Cooler
ASUS P5Q-E ATX Intel Motherboard
G.SKILL PI Black 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory
Antec CP-850 850W Continuous Power Power Supply
Antec Twelve Hundred Black Computer Case With Side Panel Window
Intel Core 2 Quad Q9550 2.83GHz LGA 775 95W Quad-Core Processor
SAPPHIRE Radeon HD 4870 X2 100251SR Video Card
Western Digital Caviar Black 640GB 3.5" SATA 3.0Gb/s Hard Drive
Scythe SCORC-1000 140mm CPU Cooler
ASUS P5Q-E ATX Intel Motherboard
G.SKILL PI Black 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory