Would you build your own Pc?
Or would you buy a Pc?
Following hardware would be suitable for you:
Cpu:AAMD Phenom II X4 955 Cpu Black EditionT ~160€
Motherboard:ASUS M4A87TD ~100€
Memory:Kingston KHX1600C9D3K2/4G 2*2 GB ~100€
Hard Drive:2...