This is my final list for my affordable gaming computer, if you see any compatibility issues or a brand that does not hold up well please let me know I am planning on ordering from Newegg in the morning. $600 is my limit.
Case: Antec Three Hundred Black Steel ATX Mid Tower Computer Case $59.95
HDD: Seagate Barracuda 7200.10 ST3250410AS 250GB 7200 RPM SATA 3.0Gb/s Hard Drive $54.99
MB: GIGABYTE GA-MA770-UD3 AM2+/AM2 AMD 770 ATX AMD Motherboard $74.99
Video Card: SAPPHIRE 100265L Radeon HD 4830 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card $99.99
PSU: CORSAIR CMPSU-400CX 400W ATX12V V2.2 80 PLUS Certified Compatible with Core i7 Power Supply $59.99
RAM: G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory $44.99
CPU: AMD Athlon 64 X2 7750 Kuma 2.7GHz Socket AM2+ 95W Dual-Core black edition Processor $77.99
OS: Microsoft Windows Vista Home Basic SP1 64-bit for System Builders $89.99
Shipping: $29.81
Total: $592.69
Case: Antec Three Hundred Black Steel ATX Mid Tower Computer Case $59.95
HDD: Seagate Barracuda 7200.10 ST3250410AS 250GB 7200 RPM SATA 3.0Gb/s Hard Drive $54.99
MB: GIGABYTE GA-MA770-UD3 AM2+/AM2 AMD 770 ATX AMD Motherboard $74.99
Video Card: SAPPHIRE 100265L Radeon HD 4830 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card $99.99
PSU: CORSAIR CMPSU-400CX 400W ATX12V V2.2 80 PLUS Certified Compatible with Core i7 Power Supply $59.99
RAM: G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory $44.99
CPU: AMD Athlon 64 X2 7750 Kuma 2.7GHz Socket AM2+ 95W Dual-Core black edition Processor $77.99
OS: Microsoft Windows Vista Home Basic SP1 64-bit for System Builders $89.99
Shipping: $29.81
Total: $592.69