A machine that can game will cost at least $900+ excluding OS,
monitor and other peripherals.
ASUS M4A78M-LE w/ AMD Phenom II X2 550BE CPU - $253
2x 2GB Team Group Xtreem Dark Elite DDR2-800 RAM - $148
Sapphire Radeon HD4850 1GB - $219
Andyson F550 80PLUS PSU w/ EPS - $89
LG DVD Writer - $34
Western Digital Caviar Black HDD 500GB - $74
CoolerMaster Elite 341 Black SECC mATX casing - $59
Optional items:
High performance CPU Cooling
Add $39 for a CoolerMaster Hyper TX3 3-HDT heatsink (comes w/
92mm fan)
Add $13 per AVC F1225B12V high airflow case fan
Add $188 if you want watercooling - Corsair H50 CPU watercool
Others
Add $10 to upgrade from mATX Elite 341 to ATX midtower Elite
310
Add $24 per set of case CCFL's from UVnium