This will be my first computer build. I'm going for a mid level gaming platform, around $500. Here's what I have:
Case: COOLER MASTER Elite 430 RC-430-KWN1 Black Steel / Plastic Computer Case
http://www.newegg.com/Product/Product.aspx?Item=N82E16811119227
MoBo: BIOSTAR A780L3C AM3 Micro ATX AMD Motherboard
http://www.newegg.com/Product/Product.aspx?Item=N82E16813138376
PSU: CORSAIR Builder Series CX430 430W ATX12V v2.3 80 PLUS BRONZE Certified Active PFC Power Supply
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026
RAM: Kingston HyperX Black Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model KHX16C9B1BK2/8
http://www.newegg.com/Product/Product.aspx?Item=N82E16820104387
CPU: AMD Athlon II X4 640 Propus 3.0GHz Socket AM3 95W Quad-Core Desktop Processor ADX640WFGMBOX
http://www.newegg.com/Product/Product.aspx?Item=N82E16819103871
Graphics: HIS iCooler H775FS2G Radeon HD 7750 2GB 128-bit DDR3 PCI Express 3.0 x16 HDCP Ready Video Card
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161427
Hard Drive: Seagate Barracuda ST1000DM003 1TB 7200 RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive
http://www.newegg.com/Product/Product.aspx?Item=N82E16822148840
Optical Drive: ASUS 24X DVD Burner:
http://www.newegg.com/Product/Product.aspx?Item=N82E16827135204
I also have 2 extra fans to supplement the one in the case...:
COOLER MASTER R4-L2R-20AC-GP 120mm Blue LED Case cooler
http://www.newegg.com/Product/Product.aspx?Item=N82E16835103060
Rosewill RFA-80-BL 80mm 4 Blue LEDs LED Case cooler
http://www.newegg.com/Product/Product.aspx?Item=N82E16835200045
...and a Wi-Fi card:
Rosewill RNX-G300LX Wireless Adapter Card
http://www.newegg.com/Product/Product.aspx?Item=N82E16833166021
Total Cost: $484.89
Case: COOLER MASTER Elite 430 RC-430-KWN1 Black Steel / Plastic Computer Case
http://www.newegg.com/Product/Product.aspx?Item=N82E16811119227
MoBo: BIOSTAR A780L3C AM3 Micro ATX AMD Motherboard
http://www.newegg.com/Product/Product.aspx?Item=N82E16813138376
PSU: CORSAIR Builder Series CX430 430W ATX12V v2.3 80 PLUS BRONZE Certified Active PFC Power Supply
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026
RAM: Kingston HyperX Black Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model KHX16C9B1BK2/8
http://www.newegg.com/Product/Product.aspx?Item=N82E16820104387
CPU: AMD Athlon II X4 640 Propus 3.0GHz Socket AM3 95W Quad-Core Desktop Processor ADX640WFGMBOX
http://www.newegg.com/Product/Product.aspx?Item=N82E16819103871
Graphics: HIS iCooler H775FS2G Radeon HD 7750 2GB 128-bit DDR3 PCI Express 3.0 x16 HDCP Ready Video Card
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161427
Hard Drive: Seagate Barracuda ST1000DM003 1TB 7200 RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive
http://www.newegg.com/Product/Product.aspx?Item=N82E16822148840
Optical Drive: ASUS 24X DVD Burner:
http://www.newegg.com/Product/Product.aspx?Item=N82E16827135204
I also have 2 extra fans to supplement the one in the case...:
COOLER MASTER R4-L2R-20AC-GP 120mm Blue LED Case cooler
http://www.newegg.com/Product/Product.aspx?Item=N82E16835103060
Rosewill RFA-80-BL 80mm 4 Blue LEDs LED Case cooler
http://www.newegg.com/Product/Product.aspx?Item=N82E16835200045
...and a Wi-Fi card:
Rosewill RNX-G300LX Wireless Adapter Card
http://www.newegg.com/Product/Product.aspx?Item=N82E16833166021
Total Cost: $484.89