We primarily use our computer for web media that includes flash games, video streaming and various social networking sites. The system we build should be a low-cost box that would excel in all areas, and still allows for some casual gaming.
Below is a budget PC that would be relatively quick for everything that you would do, without breaking the bank.
CPU: AMD Athlon II X3 445 Triple-Core Processor 3.0GHz – $100
Mainboard: Gigabyte GA-880GM-UD2H – $159
Memory: Kingston PC3-10600 2GB DDR3-1333 x 2 pc – $62
GPU: Power Color Radeon HD5750 1GB DDR5 – $155
Hard drive: Hitachi SATA-II 500GB 7200RPM 16MB – $48
Casing: Cooler Master RC-360 Elite 360 – $54
PSU: Cooler Master RP-550 550W Extreme Power – $79
Optical: Samsung SH-S223F 22X SATA DVD Burner – $27